Regulatory Programme

Asbestos Control Programme

The Asbestos Control Programme aims to eliminate asbestos-related diseases over the long term through progressive elimination of asbestos use, and the minimisation of exposure during the use and removal, and management of asbestos in buildings. Target processes include work involving removal and abatement of asbestos in buildings, vessels and other premises.
The programme involves

• strengthening the legislative requirements for asbestos removal work
• introducing a licensing scheme for asbestos removal contractors
• raising awareness and capability building; engagement and enforcement

MOM works with the Building Control Authority, National Environment Agency and other relevant stakeholders in implementing the programme.

---

Business Under Surveillance (BUS)

The Business Under Surveillance (BUS) Programme is a systemic intervention tool to regulate poor performing companies to focus on developing and implementing a robust safety and health management system to improve their WSH performance.
This programme is divided into two phases – the Assessment and the Surveillance phase. In the Assessment phase, companies who have had fatal accidents, demonstrated poor WSH management (such as poor site conditions that result in Stop Work Orders) or have had accumulate a number of demerit points would typically be considered for entry into the BUS programme. A thorough review of the implementation of the risk assessment and the strength of the management system would be conducted. If the company fails the assessment, they will be subjected to close surveillance.
In the Surveillance phase, OSHD requires the company's management to develop and commit to a comprehensive and sustainable Action Plan. The company is held accountable to their proposed Action Plan and reports the implementation progress on a regular basis to OSHD. In addition, inspections are carried out frequently by the OSHD Surveillance Branch to verify the progress made. The company will exit from the programme upon demonstrating significant improvement in its WSH performance and management.

---

Cluster operations

Cluster Operations (COPS) is a workplace inspection programme where selected cluster of workplaces are pre-announced on this website before the inspections take place. This is to encourage affected companies to take the initiative to improve safety and health standards within their workplace prior to MOM's inspections. Links to online guidelines, technical advisories and compliance assistance tools will be provided to assist companies in their preparation for the workplace inspections.

In certain clusters of workplaces, upstream stakeholders of these workplaces (e.g. client of affected companies) will also be engaged to solicit improvements in workplace safety standards within the cluster.

Outcomes of the workplace inspections conducted and common contraventions detected will be shared after each operations, to facilitate companies in the detection and rectification of weak areas within their workplaces.

Upcoming Cluster Operations are published as highlights in the Workplace Safety and Health section.

---

Confined Space Management Programme

The Confined Space Management Programme aims to enhance confined space hazard management and prevent deaths from chemical poisoning and asphyxiation during confined space work and rescue operations. Iso-tank operations in logistics, shipbuilding and ship-repairing industries, manhole works and other workplaces with confined space hazards are required to implement a confined space management programme consisting of the following elements: hazard identification, evaluation and control, entry-permit system, atmospheric testing and monitoring, ventilation and emergency response.
Initiatives include:

• identification of workplaces with confined space hazards
• raising awareness and capability building for confined space management
• implementing effective in-plant confined space programmes

---

Hazardous Chemical Management Programme

The Hazardous Chemical Management Programme covers chemical manufacturers and workplaces using hazardous chemicals. The objectives of the programme are to prevent and control chemical hazards and protect persons at work against such hazards.
Companies under the programme are required to implement an in-plant chemical management programme consisting of the following key elements: hazard communication (labelling and safety data sheet), training and education, hazard assessment and control (with respect to storage, handling and disposal of chemicals), personal protection equipment, workplace monitoring, medical surveillance, and emergency response.
The programme entails

• identification, evaluation and control of chemical hazards
• review of exposure limits
• regular monitoring or assessment of chemical exposure

Results of regular exposure monitoring are submitted to MOM and captured in our chemical exposure database. Where exposure levels are excessive, intervention actions will be taken.

---

Noise Induced Deafness Prevention Programme

The NID Prevention Programme (NIDPP) aims to reduce the incidence of Noise-induced Deafness (NID). The target of this programme includes workplaces with noise hazards in the manufacturing, shipbuilding/ship-repairing and construction sector, through a series of outreach and enforcement activities. Key elements of the in-plant HCP include noise monitoring, noise control, hearing protection, audiometric examinations and health education.
Initiatives under this programme include:

• strengthening legislative requirements
• identifying noisy workplaces for surveillance and control
• managing noise hazards at workplaces through the implementation of in-plant Hearing Conservation Programme (HCP)
• raising awareness and building capability in noise hazard management

Environmental Legislation Associated with Development of Industrial Building

Pollution Control

The Environmental Protection and Management Act (EPMA) & Regulations provide for and
regulate the installation, operation and maintenance of the industrial plant and pollution
control facilities. It also regulates the limits for emission of air impurities into atmosphere,
discharge of wastewater into watercourse and the factory boundary noise. The EPMA
requires a Clearance Certificate to be obtained before the commencement of any industrial
plant work and a Compliance Certificate to be obtained after satisfactory completion of any
industrial plant work.

Environmental Health

The Environmental Public Health Act and Regulations provides for and regulates the
installation, operation and maintenance of the solid waste management facilities in
developments.

Sewerage

The Sewerage and Drainage Act (SDA) provides for and regulates the construction,
maintenance and improvement of sewerage system. It also regulates the discharge of
sewage and trade effluent and for matters connected therewith.

The Sewerage and Drainage Act requires:
a) Clearance Certificate to be obtained before the commencement of any sewerage
and sanitary works
b) Compliance Certificate to be obtained upon satisfactory completion of any sewerage
and sanitary works
c) Approval to be obtained before carrying out any building/structure works, piling
works or temporary structure works over, across or adjacent to any sewer or
sewerage system
d) Approval to be obtained before the discharge of any trade effluent into public
sewers

Drainage
The construction, maintenance, improvement and safeguard of land drainage systems are
regulated under Sewerage and Drainage Act (SDA) and the Sewerage and Drainage (Surface
Water Drainage).

Environment Control
 
The Sewerage and Drainage Act requires:
a) Clearance Certificate to be obtained before the commencement of any storm water
drainage works, or to erect or place any structures or object in, above or across any
drain or drainage reserve
b) Compliance Certificate to be obtained upon satisfactory completion of any storm
water drainage works, erection or placement of any structures or object in, above or
across any drain or drainage reserve
c) Approval to be obtained before carrying out any temporary structure works/services
over, across or adjacent to any drain or storm water drainage system
d) Approval to be obtained before construction of any works for taking or intercepting
water from any place or sea, within the territorial limits of Singapore
Who are the parties involved?
a) Developer appoints a process consultant or Qualified Persons (QP- Registered
Architect or Professional Engineer) to prepare and submit the necessary applications
to obtain Industrial Allocation clearance, Development Control clearance, Building
Plan clearance certificates, Temporary Occupation Permit clearance and Certificate
for Statutory Completion clearance (Compliance Certificate)
b) QP shall also supervise, inspect the building works and certify completion of building
works in accordance to the environmental codes

LEGISLATION ON ENVIRONMENTAL SUSTAINABILITY FOR BUILDINGS

As Singapore aspires to be a leading global city in environmental sustainability, there is scope to further improve on energy efficiency requirements in buildings, to address the impact of climate change. While the focus on energy efficiency remains important, a more holistic approach was taken to encourage environmental friendliness in buildings to ensure that environmental quality and comfort are not compromised. Among other initiatives, BCA has enhanced the Building Control Act and put in place the Building Control (Environmental Sustainability) Regulations, to require a minimum environmental sustainability standard that is equivalent to the Green Mark Certified Level for new buildings and existing ones that undergo major retrofitting. This regulation took effect from 15 Apr 2008. Projects that are submitted for URA planning permission on or after 15 Apr 2008 will be subject to this requirement.

SCOPE AND DETAILS

The Building Control (Environmental Sustainability) Regulations will apply to :

• All new building works with gross floor area of 2000 m² or more ;
• Additions or extensions to existing buildings which involve increasing gross floor area of the existing buildings by 2000 m² or more;
• Building works which involve major retrofitting to existing buildings with existing gross floor area of 2000 m² or more.

Alteration to existing buildings which does not involve major retrofitting works is not subject to this requirement. 

The requirements on environmental sustainability of buildings will be integrated with the building plan process. The qualified person who submits the building plan and the other appropriate practitioners will be responsible for assessing and scoring the building works under their charge using the criteria and scoring methodology spelled out in the Code.

The minimum environmental sustainability standard will be revised with effect from 1 Dec 2010.  The compliance with the respective environmental sustainability standards will be based on the first submission date for URA planning permission as stated in the table below.

1st submission date for URA planning permission	Compliance Standard
From 15 Apr 2008 to 30 Nov 2010	Code for Environmental Sustainability for  Buildings, 1st Edition, Apr 2008 issue
From 1 Dec 2010 and onwards	Code for Environmental Sustainability for  Buildings, 2nd Edition, Aug 2010 issue

Here are the administrative details

		Green Mark (GM) e-Filing System For submission in compliance with BC (Environmental Sustainability) Regulations 2008
GM submission at BP stage	For Projects with 1st submission date to URA planning permission on or after 1st Dec 2010	Green Mark score calculations for residential buildings Green Mark score calculations for non-residential buildings Note : These forms are to be generated from Green Mark (GM) e-filing system.
	For Projects with 1st submission date to URA planning permission from 15 Apr 2008 to 30 Nov 2010	Green Mark score calculations for residential buildings Green Mark score calculations for non-residential buildings Note : These forms are to be generated from Green Mark (GM) e-filing system.
As-built GM submission before TOP stage	For Projects with 1st submission date to URA planning permission on or after 1st Dec 2010	As-built Green Mark score calculations for residential buildings As-built Green Mark score calculations for non-residential buildings Note : These forms are to be generated from Green Mark (GM) e-filing system.
	For Projects with 1st submission date to URA planning permission from 15 Apr 2008 to 30 Nov 2010	As-built Green Mark score calculations for residential buildings As-built Green Mark score calculations for non-residential buildings Note : These forms are to be generated from Green Mark (GM) e-filing system.

 
MANDATORY HIGHER GREEN MARK STANDARD FOR GOVERNMENT LAND SALES SITES IN SELECTED STRATEGIC AREAS

To maximise the potential for cost-effective energy savings in our built environment, it was announced in BCA’s 2nd Green Building Masterplan in 2009 that projects developed on land sold under the Government Land Sales (GLS) Programme sites in the selected strategic areas will be subject to higher Green Mark Standards.

 
SCOPE AND DETAILS

This requirement will apply to buildings works related to any building on land sold on or after 5 May 2010 under the Government Land Sales Programme in selected strategic areas. The building works subject to this requirement are to be designed to meet the prescribed Green Mark Certification as shown in the following table.

Selected Strategic Areas Exact Location to refer to the Building Control (Environmental Sustainability ) Regulations 2008	Requirements for building wholly or partly within area that is on land sold under the Government Land Sales Programme
Marina Bay	Green Mark Platinum Rating
Downtown Core – including areas within the CBD located next to Marina Bay	Green Mark GoldPlus Rating
Jurong Lake District	Green Mark GoldPlus Rating
Kallang Riverside	Green Mark GoldPlus Rating
Paya Lebar Central	Green Mark GoldPlus Rating

For building works that are subject to this requirement, the qualified person and appropriate practitioners need not submit their declarations of the Green Mark scores along with the building plan submission. Instead, the qualified person should ensure that, prior to the building plan submission, an application is made to BCA for the project to be assessed certified under the certification standards approved by the Commissioner of Building Control. Upon completion of the building works, the qualified person should submit the Green Mark Certificate showing the Green Mark Certification rating achieved for the project along with his application for a temporary occupation permit (TOP) or certificate of statutory completion (CSC). It is important to note that the prescribed Green Mark Certification rating for the building has to be obtained before a TOP/ CSC can be granted.

The certification standard will be revised from 1 Dec 2010 in tandem with the changes in the Green Mark Criteria.  The compliance with the respective certification standards will be based on the tender award letter issued by URA to the successful developer under the Government Land Sales (GLS) programmes for the selected strategic areas and as stated in the table below.

Date of Tender Closed under the GLS programmes	Compliance Standard
From 5 May 2010 to 30 Nov 2010	BCA Green Mark Certification Standards for New Building, GM Version 3.0, May 2010 issue
From 1 Dec 2010 and onwards	BCA Green Mark Certification Standards for New Building, GM Version 4.0, Aug 2010 issue

MANAGEMENT OF TOXIC INDUSTRIAL WASTES IN SINGAPORE

MANAGEMENT OF TOXIC INDUSTRIAL WASTES IN SINGAPORE

1 Introduction

1.1 Wastes may be defined as materials which no longer can be used for the purposes they were intended for originally. Toxic industrial wastes are wastes which by their nature and quality may be potentially detrimental to human health and/or the environment and which require special management, treatment and disposal.

1.2 In view of Singapore’s small land area with limited land and water resources, the siting of industries has to be carefully planned and managed. In addition, industries are required to design their manufacturing processes and provide pollution control facilities to comply with pollution control requirements on emission of air pollutants, discharge of industrial effluent, management of hazardous substances and toxic industrial wastes.

1.3 There are currently more than 2,000 companies in Singapore which handle or use hazardous chemicals. The use of these chemicals generates a wide variety of toxic industrial wastes. The main types are spent acids, spent solvents, spent etchants, waste oil and other waste sludge.

2 Strategy for Control of Toxic Industrial Wastes
2.1 The key elements in Singapore’s strategy to control toxic industrial wastes and ensure their safe treatment and disposal are as follows:
(i) avoid generation of intractable wastes;
(ii) encourage waste minimisation;
(iii) encourage waste reuse, recovery and recycling;
(iv) regulate collection, treatment and disposal;
(v) monitor and audit collection, treatment and disposal; and
(vi) promote and support educational and training programmes.
2.2 All new industrial developments are screened by PCD at the planning stage. One of the key areas checked in this screening
2
process is the generation and disposal of wastes from proposed industrial developments. PCD will approve the proposed industrial development only if the wastes generated could be safely disposed of in Singapore. This avoids the generation of intractable wastes that cannot be safely disposed of in Singapore.
2.3 In addition, PCD will require industries to use processes that minimise waste generation or facilitates the reuse, recovery and recycling of the wastes. Industries also need to incorporate measures into the design of their facilities to ensure wastes generated can be properly handled and managed. At the building plan stage, checks are made to ensure that these measures are incorporated into the design of the plants.
2.4 PCD has encouraged the setting up of specialised waste recycling, treatment, and disposal plants. There are currently about 100 such plants in Singapore, treating and recycling a wide range of toxic industrial wastes. Some of the toxic industrial wastes collected and recycled by these plants for reuse are discussed in Section 5.
2.5 The setting up of specialised waste recycling, treatment and disposal plants serve to help industries, especially the smaller companies, which may generate small quantities of special wastes but find it impractical or uneconomical to install, operate and maintain a waste treatment facility because of cost, lack of expertise or space constraint.
2.6 The collection, recycling, treatment and disposal of toxic industrial wastes are controlled under the Environmental Public Health Act (EPHA) and the Environmental Public Health (Toxic Industrial Waste) Regulations (TIWR).

3 The Environmental Public Health (Toxic Industrial Waste) Regulations (TIWR)
3.1 The control on the import, sale, supply, receipt, transport, treatment and disposal of toxic industrial (hazardous) wastes are regulated under the TIWR. Industrial wastes controlled under the TIWR are listed in the Schedule of the Regulations as waste streams from specific industrial activities, wastes with specified toxic components and as specific categories of wastes. The list includes spent acids, alkalis, wastes containing gallium arsenide, spent etching solutions containing copper from printed circuit board manufacturing, etc. The list is at the Annex.
3
3.2 In order to facilitate controls and proper management, the functions and responsibilities of key persons involved in handling of the toxic industrial wastes are clearly delineated in the TIWR. The key persons include the following:
(a) Generator of wastes
(b) Collector
(c) Carrier or transporter
(d) Driver
3.3 The generator will have to treat the wastes in an approved in-house waste treatment plant and dispose of the residues, if any, at NEA sanitary landfill site. Alternatively, the generator can engage a licensed toxic industrial waste collector to collect his wastes for treatment and disposal.
3.4 A toxic industrial waste collector is a person who receives toxic industrial wastes for storage, reprocessing, treatment and disposal. He has to obtain a licence from PCD to collect specific toxic industrial wastes that are listed in his licence and confine his wastes storage and treatment activities to approved premises and facilities.
3.5 Written transport approval from PCD is also required for the transportation of wastes in quantities which exceed those specified in the TIWR. The responsibilities of the following key persons in the transportation are clearly defined in the TIWR:
(a) Consignor - the person who presents a consignment of controlled wastes for transport. The consignor can be either the generator or the licensed collector. Transport approval shall be obtained from PCD to transport the wastes.
(b) Carrier - the person who undertakes the transport of the controlled wastes. He can either be the generator, the licensed collector or the transport company engaged by either one of them.
(c) Consignee - the person who receives the controlled wastes. He is usually the licensed collector.
4
(d) Driver - the driver of the vehicle transporting the toxic industrial wastes.
3.6 To prevent illegal dumping and disposal of toxic industrial wastes, the movement of every consignment of wastes from a generator through a carrier to a collector is tracked by means of an Internet-based electronic submission of consignment note system (known as the e-Tracking System).

4 Waste Minimisation
4.1 The Waste and Resource Management Department (WRMD) of NEA is to formulate policies to promote and spearhead waste minimisation in Singapore. WRMD develops, promotes and oversees the implementation of programmes on waste minimisation and recycling. It also carries out studies to enhance waste recycling.
4.2 WRMD together with PCD works closely with the industries to promote waste minimization. Some of the activities promoted by WRMD and PCD are as follows:
(a) Waste Exchange
NEA helps to link industries for exchange of wastes. Waste to one company may be a resource to another. For example, waste alkali generated by one company could be used by another company to neutralise the acidic wastes. This would minimise the ultimate quantity of wastes to be disposed of.
(b) Use of Clean Technology
At the planning consultation stage, NEA advises and encourages industries to use clean technologies which minimise waste generation.
(c) Reuse and Recycling
NEA encourages the recycling and reuse of wastes and assists in the setting up of waste recycling plants. Some of the wastes that are being recycled and reused in Singapore are discussed in Section 6.
(d) Waste Audit
NEA encourages those industries that generate large quantities of wastes to carry out waste audit. A waste audit is designed to achieve maximum resource optimisation and improved process performance. The audit enables one to take a comprehensive look at the process to understand the material flows and to focus on areas where waste reductions are possible. The waste audit can be carried out to cover a complete process or to concentrate on a selection of unit operations within a process. There are competent consultants in Singapore to carry out such waste audit for industries.

5 Some Practices Adopted for Recycling and Reuse of Wastes
5.1 A large amount of industrial wastes generated and collected in Singapore by the licensed collectors are either recycled, reused or have valuable components extracted and recovered before disposal. Such wastes include spent solvents, spent etchants and photographic wastes.
5.2 Spent solvents are generated by a wide range of industries. Each year about 50,000 m3 of spent solvents are collected by the licensed collectors. The spent solvents collected include acetone, chloroform, ethyl acetate, methylene chloride and toluene. About 22,500 m3 of spent solvents are recovered by distillation. The practice adopted by these collectors is usually batch (differential) distillation. The equipment comprises a still to vapourise the solvents, a condenser to condense the vapours and collecting vessels to collect the condensate and the residues. The recovered solvents are sold for reuse by industries. The remaining 27,500 m3 of spent solvents that could not be recovered are used as supplementary fuel for toxic waste incinerators.
5.3 Printing and film processing activities generate photographic wastes such as spent fixers and bleaches. Each year about 1,000 m3 of such wastes are collected and treated. These wastes contain silver in solution. An effective and commercially viable method, the electrolytic extraction process, is used to recover the silver. In this process, carbon is used as the anode and a stainless steel drum as the cathode. The silver is deposited on the stainless steel drum. The extracted silver has a purity of more than 90 %. The remaining liquid from the electrolysis process is treated and neutralised in a waste water treatment plant before discharge into the sewers.
5.4 Etching is an important process used in the electronics industry especially in the manufacture of the printed circuit boards. The process generates spent etchants such as cupric chloride etchants,
6
ferric chloride etchants and ammonia etchants. Each year about 23,000 m3 of spent etchants are generated and treated in Singapore. Spent ferric chloride etchants are regenerated using scrap iron and chlorine. In this process, scrap iron is first added to the spent etchant and the copper sludge that precipitates out is collected and sold as a valuable by product. The etchant is next regenerated by passing chlorine through it. The regenerated etchant is sold for reuse.
6 Monitoring And Enforcement
6.1 Any control system, no matter how well crafted will not be effective without rigorous enforcement. Enforcement will ensure the minority of companies that violate the controls are penalised accordingly and would not gain unfairly from their violations. Without rigorous enforcement, companies that originally comply with the controls may become complacent and pay less attention and effort to ensure their operations continue to be safely managed.
6.2 Monthly checks are conducted on premises of toxic industrial waste collectors and the records are audited to ensure requirements on collection, storage, treatment and disposal of toxic wastes are complied with.
7 Transboundary Movements Of Hazardous Wastes
7.1 Before acceding to the Basel Convention, Singapore had already adopted and practised the principles of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and its Disposal in controlling the export, import and transit of toxic industrial wastes or hazardous wastes.
7.2 Singapore acceded to the Basel Convention on 2 Jan 96 and on 16 Mar 98 enacted The Hazardous Waste (Control of Export, Import and Transit) Act and its Regulations to strengthen the control on export, import and transit of hazardous wastes in accordance with the principles and provisions of the Basel Convention.
7.3 Under the Hazardous Waste Act and its Regulations, any person who wishes to export, import or transit hazardous wastes shall obtain a permit from PCD. PCD has adopted the Prior Informed Consent (PIC) procedure of the Basel Convention in granting any permit for the export, import or transit of hazardous wastes.
7
8 Training
8.1 NEA collaborates with local institutions and trade associations such as the universities, the Singapore Chemical Industry Council, the Society for Loss Prevention in the Oil, Chemical and Process Industries, etc, to organise and conduct workshops, conferences and seminars on the safe handling and disposal of toxic industrial wastes for local industries.
8.2 NEA also works together with the Occupational Safety and Health Division of the Ministry of Manpower to conduct training courses on safe practices on handling of toxic industrial wastes for workers in the industries.
9 Conclusion
9.1 In addition to regulatory controls, the co-operation of industries in ensuring that toxic industrial wastes are properly managed and disposed of in Singapore is essential. NEA will continue to work with industry and institutions in promoting better management and disposal of toxic industrial wastes through joint research and educational programmes.
9.2 NEA will continue to participate in international events on the Basel Convention and adopt and practise the principles of Basel Convention in dealing with transboundary movements of toxic industrial wastes.
8
ANNEX
LIST OF TOXIC INDUSTRIAL WASTES CONTROLLED UNDER THE
ENVIRONMENTAL PUBLIC HEALTH (TOXIC INDUSTRIAL WASTE) REGULATIONS
List of Toxic Industrial Wastes
Acids
1 Spent inorganic acids.
Eg. hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid, hydrofluoric acid, boric acid and pickling acid.
2 Spent organic acids.
Eg. acetic acid, formic acid, benzoic acid and sulphonic acid
Alkali
1 Spent alkaline solutions
2 Spent ammoniacal solutions
3 Metal hydroxide sludges and oxide sludges
Antimony and its Compounds
4 Spent antimony potassium tartrate
Arsenic and its Compounds
1 Timber preservative residues containing arsenic
2 Wastes containing gallium arsenide
Asbestos
1 Asbestos wastes from
Chromium Compounds
1 Plating effluent and residues containing chromium
2 Timber preservative residues containing chromium
3 Spent and aqueous solutions containing chromic compounds
4 Tannery effluent and residues containing chromium
Copper Compounds
1 Plating effluent and residues containing copper
2 Spent etching solutions containing copper from printed circuit board manufacturing
3 Timber preservative residues containing copper
Cyanides
1 Plating effluent and residues containing cyanides
2 Heat treatment residues containing cyanides
3 Spent quenching oils containing
9
asbestos/cement manufacturing processes
2 Empty sacks/bags which have contained loose asbestos fibre
3 Asbestos wastes generated from industrial activity, demolition, renovation and delagging works and ship repairing
Cadmium and its Compounds
1 Plating effluent and residues containing cadmium
2 Wastes containing cadmium from Ni/Cd battery manufacturing
cyanides
4 Spent processing solutions containing cyanides from photographic processing
Fluoride Compounds
1 Timber preservative residues containing fluorides
2 Spent ammonium bi-fluoride
10
ANNEX (CONT'D)
List of Toxic Industrial Wastes
Isocyanates
1 Spent di-isocyanates.
Eg. toluene di-isocyanate (TDI) and
methylene di-isocyanate (MDI) from
polyurethane foam-making process
Laboratory Wastes
1 Obsolete laboratory chemicals
2 Toxic chemical wastes from chemical analysis
Lead Compounds
1 Sludges containing lead oxide/sulphate
2 Spent organo-lead compounds.
Eg. tetraethyllead (TEL) and
tetramethyllead (TML)
3 Waste lead-acid batteries, whole or crushed
Mercury and its Compounds
1 Effluent, residues or sludges containing mercury from chlor-alkali industry
2 Wastes containing mercury from equipment manufacturing involving the use of metal mercury
3 Spent catalysts from chemical processes containing mercury
4 Spent organo-mercury compounds
Organic Compounds containing Halogen
1 Spent halogenated organic solvents.
Eg. trichloroethylene, 111-trichloroethane, perchloroethylene, methylene chloride
tetra-chloromethane and
112-trichloro-122-trifluoroethane
2 Residues from recovery of halogenated
organic solvents
3 Packaging materials or residues containing chlorobenzenes and/or chlorophenols and
their salts
Organic Compounds not containing Halogen
1 Spent non-halogenated organic solvents.
Eg. benzene, toluene, xylene, turpentine, petroleum, thinner, kerosene, methanol, ethanol, isobutanol, isopropanol, methyl ethyl ketone, methyl isobutyl ketone, isopropyl ether, diethyl ether, hexane, dimethyl sulphide and dimethyl sulphoxide
2 Residue from recovery of non-halogenated organic solvents
11
Metal Catalysts
1 Spent metal catalysts from chemical
processes and petroleum refining.
Eg. Catalysts containing chromium cobalt
Nickel Compounds
1 Plating effluent and residues containing nickel
Other Wastes
1 Obsolete/abandoned chemicals and pesticides from storage, manufacturing and trading activities
2 Used containers, bags and process equipment contaminated by chemicals and pesticides from storage, manufacturing and trading activities
3 Wastes/residues containing unreacted monomers. Eg. vinyl chloride and styrene monomers, from polymer manufacturing processes
4 Tar residues from distilling and tarry materials from refining
12
ANNEX (CONT'D)
List of Toxic Industrial Wastes
5 Wastes from toxic waste treatment processes. Eg. wastes and residues from solidification, fixation and incineration processes
6 Wastes from toxic chemical drums and tank cleaning activities
7 Chemical and oil slops from ship tankers
8 Wastes from the production, formulation and use of resins, latex, plasticisers, glues/adhesives containing solvents and other contaminants.
9 Wastes from the production, formulation and use of inks, dyes, pigments, paints, lacquers, varnish containing organic solvents, heavy metals or biocides.
10 Solid wastes and sludges or obsolete/off specification materials not categorised elsewhere in the Schedule and failing the NEA’s landfill disposal criteria
Pathogenic Wastes
1 Pathogenic wastes from hospitals
2 Pathogenic wastes from healthcare and research institutions, clinics and laboratories
Pharmaceutical Wastes
1 Pharmaceutical wastes comprising antineoplastic agents, antibiotics,
Polyvinyl Chloride (PVC)
1 All waste materials containing PVC. Eg. PVC insulated wires, PVC pipes and trunking, PVC parts, PVC upholstery and PVC resins
Silver Compounds
1 Spent processing solutions containing silver from photographic processing
Used, Contaminated Oil
1 Used mineral, lubricating and hydraulic oil from machine cylinders, turbines, switch gears and transformers
2 Spent motor oils from petrol and
diesel engines
3 Spent quenching oil from metal hardening
4 Oil recovered from solvent degreasers
5 Spent oil water emulsions.
Eg. Spent coolants from metal
Working industries
6 Oil water mixtures (mainly oil).
Eg. Oily ballast water from ship tankers
13
vaccines and other immunological products, controlled drugs under the Misuse of Drugs Act (Cap. 185) and pharmaceutical wastes containing arsenics, cyanides and heavy metals and their salts
Phenolic Compounds
1 Sludges/residues from paint stripping using chemicals containing phenols
2 Residues containing unreacted phenol and formaldehyde from adhesive industry
Polychlorinated Bi-phenyl (PCB) including Polychlorinated Ter-phenyl (PCT)
1 Spent transformer oil containing PCB
and/or PCT
2 Rectrofilled transformer contaminated
with PCB and/or PCT
3 Electrical equipment and parts containing or contaminated with PCB and/or PCT.
Eg. capacitors and transformers
4 Containers and all waste materials contaminated with PCB and/or PCT
7 Oil and sludge from oil interceptors
8 Tanker sludges and oil sludges/ residues from storage tanks
9 Oil sludges containing acid from recovery and recycling of used oil
Zinc Compounds
1 Plating effluent and residues containing zinc

Refer to the latest update on Singapore Statues Online.

Management of Hazardous Substances

Management of Hazardous Substances

1 INTRODUCTION
Singapore is an island of about 620 square kilometres in area. The average population density in Singapore is about 4,000 people per square kilometre. Such high population densities make it imperative for hazardous substances to be controlled so that public exposure to accidental release is, if not avoided, minimised.
In addition, large parts of Singapore are used as water catchment areas. It is necessary to ensure that chemical storage facilities and transport avoid such areas as far as possible. This is to prevent pollution and to protect drinking water sources against contamination.
The awareness of the hazards or risks posed to both human health and the environment from the manufacturing, storage, transport, and use of hazardous chemicals has come about in recent years as a result of a number of reported major industrial accidents in both developed and the developing countries. Two well known catastrophic incidents occurred in the mid 1980s in the less developed countries. These were the release of toxic methyl isocyanate from a pesticide factory in Bhopal, India and the explosions and fires at an LPG installation in Mexico. Both incidents caused great losses of lives.
In Singapore, the Government has implemented measures to control and minimise the risks from industrial developments handling large quantities of hazardous substances not only to protect workers within the hazardous plants but also the general public and the environment.
Pollution Control Department (PCD) of the National Environment Agency controls toxic and environmentally hazardous chemicals under The Environmental Protection and Management Act (EPMA) and The Environmental Protection and Management (Hazardous Substances) Regulations.
Flammable petroleum products in Singapore are controlled under the Fire Safety Act by the Fire Safety & Shelter Department (FSSD) of the Singapore Civil Defence Force (SCDF).
Radioactive substances are controlled by the Centre for Radiation Protection and Nuclear Science (CRPNS).
2 POLLUTION CONTROL DEPARTMENT
CONTROL STRATEGIES
The hazardous chemicals controlled by PCD (see Table 1) are those that:

• Pose a mass-disaster potential
• Are highly toxic and polluting
• Generate wastes which cannot be safely and adequately disposed of

In Singapore, the control of hazardous chemicals are implemented mainly through the following measures:

• Planning control
• Licensing control
• Enforcement

PLANNING CONTROL
On new developments, PCD checks and ensures that new residential and industrial developments are properly sited and are compatible with surrounding land use. PCD also imposes environmental pollution control requirements to be incorporated into designs of developments to minimise pollution and to mitigate pollution impact on surrounding developments.
The Jurong Town Corporation (JTC) and Housing Development Board (HDB) are developing agencies for industrial land and premises and they consult PCD on the allocation of industrial premises. PCD assesses and evaluates the environmental impact of the proposed industries to ensure that they do not pose unmanageable health and safety hazards and pollution problems. A proposed industry will be allowed only if emissions of pollutants can comply with standards, wastes can be safely managed and properly disposed of, and the factory can be sited in a suitable industrial estate.
For major developments, PCD requires developers to carry out pollution control assessment for their proposals. Examples of major developments include industries involving the use or storage of hazardous chemicals in bulk quantities, port development, landfill site, etc. The study includes an assessment of all pollution impact on the environment and recommendation of measures to mitigate such impact. PCD will issue clearance to the proposed development only if its evaluation of the study reports confirms that pollution impact could be mitigated to acceptable levels.
In addition, PCD encourages industries to reuse, recycle and recover their by-products to minimise waste generation. Disposal of wastes by landfill is only used as a last resort. For proposed industrial developments, PCD also checks and ensures that clean technology is adopted in industrial processes to conserve resources, and minimise pollution.
After a proposed development has been granted planning approval, a developer can proceed to submit building plans to the Building Control Division (BCD) of the Public Works Department for approval. Under the current procedure on building plan approval, the developer is also required to submit building plans to technical departments including PCD for clearance on technical requirements. PCD checks the building plans of the development for compliance with technical requirements on environmental health, drainage, sewerage and pollution control. In addition, PCD also checks and ensures that pollution control measures are incorporated into the design of buildings.
After the completion of a development, PCD inspects it to ensure compliance with technical requirements before granting clearance to BCA for the issue of Temporary Occupation Permit (TOP)/Certificate of Statutory Completion (CSC) to the completed development.
Industries are required to apply for written permission, licence and permits from PCD before they can start operation.
LICENSING CONTROLS
Licensing controls are implemented under the Environmental Protection and Management Act (EPMA) and the Fire Safety Act. The licensing controls prevent unauthorised persons from handling such substances and ensure proper safeguards are taken at all times in the handling of the substances to prevent accidental releases and mitigate the adverse effects if they occur.
The following Licensing Controls over the import, transport, storage and use of hazardous substances are implemented under The Environmental Protection and Management Act (EPMA) and its Regulations:
Hazardous Substances Licence Control
Any person who wishes to import, sell or export any hazardous substance controlled under the Environmental Protection and Management Act (EPMA) must obtain a Licence.
A licence will be issued to a person if:

• he could show proof that the Hazardous Substances will be stored safely in an approved location and in compliance with the storage requirements;
• the use of the Hazardous Substances at his factory has been approved;
• he has sat and passed the Management of Hazardous Substances Course conducted by Singapore Environment Institute (SEI); and
• his academic qualification must be at least a technical diploma.

Hazardous Substances Permit Control
Any person who wishes to purchase, store and/or use any hazardous substance controlled under the Environmental Protection and Management (Hazardous Substances) Regulations must obtain a Permit.
A Permit will be issued to a person if:

• he could show proof that the Hazardous Substances will be stored safely in an approved location and in compliance with the storage requirements;
• the use of the Hazardous Substancesat his factory has been approved; and
• he has declared that he has read and understood the Environmental Protection and Management Act (EPMA) and its Regulations.

The Licence/Permit application form is in Annex 9. In addition, the public can submit an electronic application for a Hazardous Substances Licence/Permit via the Internet. The Internet address is: http://app1.env.gov.sg/pcls/index.jsp
Transport Approval Control
Any person who wishes to transport any hazardous substance in quantities exceeding those specified in the Environmental Protection and Management (Hazardous Substances) Regulations (see Table 2) must obtain a Transport Approval. The limits varies from 0 kg for highly toxic chemicals such as organochlorines pesticides to 1000 kg for corrosives such as sulphuric acid.
A Transport Approval will be issued to a person if:

• he holds a Licence to handle hazardous substances,
  he could show proof that the Hazardous Substances will be transported safely in compliance with the transportation requirements.

The licence holder can also submit an application for a Hazardous Substances Transport Approval via the internet.
Import Control
The most effective stage of control to ensure that all chemicals that enter Singapore can be and will be safely managed and handled at all times by approved competent licence holders is at the import stage.
Under the Environmental Protection and Management Act (EPMA), all import of Hazardous Substances listed under Second SchedueI of the Act must be approved by PCD. PCD will approve the import only if:

• the Hazardous Substances are stated in the importer's licence,
• there is a valid transport approval for the Hazardous Substances if the Hazardous Substances are to be transported out of the port.

TECHNICAL REQUIREMENTS UNDER LICENSING CONTROLS
The Environmental Protection and Management Act (EPMA) and its Regulations provide provisions for technical requirements to be imposed and complied with to ensure the safe management and handling of hazardous substances and to prevent an accident from occuring. These technical requirements are briefly described below.
Storage Requirements
The storage area should be sheltered; fenced-up; under lock and key; provided with kerb/hump all round the storage area; provided with fire protection and safety facilities; equipped with leak detection and warning devices and emergency scrubbing systems for storage of toxic gases.
The containers and storage tanks for the chemicals must be designed, manufactured and tested in accordance to an internationally-acceptable standards.
Hazardous Substances Licence and Permit holders must keep records of stock movements of the hazardous substances in accordance to the formats specified by PCD.
Adequate emergency action plan (see Annex 1) for dealing with any accidental release of chemicals must be drawn; with adequate stock of emergency equipment such as neutralising agent, adsorbents, oversized drums, protective gears, etc on kept on standby.
The implementation of a safety audit procedure is strongly encouraged to systematically identify and rectify weaknesses in the management system and practices of handling hazardous chemicals on a regular basis. Attached are the elements that should be audited and a list of consultants that are able to conduct such audits. (see Annex 2 & 3)
Transport Requirements
The containers and tankers used for bulk chemical transportation must be designed, manufactured and tested in accordance to an internationally-acceptable standards. The tankers must be certified by an approved third party inspection body to have met the stipulated standards (see Annex 4) before it can be used for transportation on Singapore roads.
The containers, tankers and vehicles must be properly labelled and carry appropiate hazard warning panels.
All transportation of controlled Hazardous Substances must strictly adhere to NEA's approved routes and must be between 9.00 am and 5.00 pm (Monday to Saturday excluding Sundays and Public Holidays).
All drivers must be trained in the handling of accidental spills and have attended the HazMat Driver Course conducted by SCDF's Civil Defence Academy or Singapore Port Institute (PSA Institute). Drivers renewing their Hazardous Material Transport Driver Permit (HTDP) are required to attend  the HazMat Driver's Course once every 2 years.
An adequate transportation emergency response plan (TERP) (see Annex 5) must also be put up to deal with any accidental release of the hazardous substances; with adequate stock of emergency equipment carried on the vehicles; such as chemical fire extinguisher, neutralising agent, adsorbents, oversized drums, protective gears, etc.
The consignor has to prepare a set of instructions for the carrier or transport company containing the following :-

• information on the hazards of hazardous substance and safety precautions for its safe handling,
• restrictions on the mode of transport and any necessary routing instructions,
• special operational requirements for loading, unloading and transport or a statement that none is needed,
• emergency response plan for transportation of the hazardous substances.

The carrier is required to obtain a set of the above instructions from the consignor and be conversant with the information it contained before proceeding to transport the consignment of the hazardous substance. The carrier must instruct and train his driver to ensure he understood the instructions given and is capable of carrying them out effectively. All documents pertaining to the chemicals transported (i.e. MSDS, transport approval and all emergency response, spill control and first aid equipment) should be kept within ready reach in event of emergency.
The consignor has to ensure that the instructions given to the carrier are accurate and sufficient to enable the carrier to carry out the transportation safely. The consignor is also required to be present on-site to personally deal with any chemical release during transportation.
Tanks of road tankers and tank containers used for transporting hazardous substances must meet approved standards of design, construction and testing. The design of the tanks must be reviewed and its construction surveyed by an approved third party inspection body. Once the third party inspection body is satisfied that the tank or tank container meets the approved standards, it will issue an initial inspection certificate. Under the approved standards, the tank and tank container must undergo periodic inspections.
The following standards are acceptable:

• European Agreement of Road Transport of Dangerous Goods (ADR Standards)
• United Nations Recommendations on the Transport of Dangerous Goods (UN Standard)
• International Maritime Dangerous Goods Code (IMDG Code)
• United States Code of Federal Regulations (US-DOT Standards)

The carrier needs to ensure that the vehicle and its tanks or containers are properly labelled in accordance to the Singapore Standards 286, 'Cautionary Labelling for Hazardous Substances'.
Labels are given for each class of hazardous substances and should be affixed on packagings and the vehicle. Road tankers and vehicles carrying hazardous substances in tank containers should have Emergency Information Panels. These are hazard warning panels containing the following emergency information :-

• the appropriate class label and subsidiary risk label, if any
• the correct technical name of the substance
• the UN number of the substance
• the Hazchem code number
• contact numbers and names of company and emergency response authority

EMERGENCY RESPONSE PLAN
Notwithstanding the controls and precautions taken, one cannot rule out the possibility of spillages and accidental releases of hazardous substances during transportation. With well drawn up emergency plans and proper training, such releases can be effectively contained and the damage to the environment and dangers to the health and safety of public minimised.
As a condition for granting licences and transport approvals, companies are required to put up emergency response plans.
The plan must be comprehensive and should contain the following key elements :-

• notification procedures; (persons and authorities to contact and how to contact)
• emergency procedures to contain and decontaminate spills; (immediate actions to be taken by driver/ground staff and actions to be taken by the company upon being informed)
• emergency equipment to be carried on the vehicle and at base such as personal protection equipment, absorbents, neutralising solutions and salvage drums;
• Material Safety Data Sheets of the hazardous substances transported.

The emergency response plan (ERP) shall be vetted and approved by SCDF before a Transport Approval may be issued.
Under the provisions of The Environmental Protection and Management (Hazardous Substances) Regulations, in the event of a chemical fire / release, the licence holders\transport approval holders are required to:

• block off the area contaminated by the hazardous substance;
• notify SCDF and the PCD;
• take immediate action to have the area decontaminated and return the situation to normal.

ENFORCEMENT
Under the Act and its Rules, PCD officers are empowered to carry out regular inspection to check into the following aspects of controls:

• Import, purchase and sale of Hazardous Substances
• Storage
• Transportation
• Labelling
• Maintaining and updating of records and sales documents
• Ensure that all hazardous substances are safely disposed of

PCD officers are authorised to:

• check and search premises;
• extracts records and documents for investigations; and
• conduct surprise checks on road tankers used for transportation on the road.

CONCLUSION
Hazardous chemicals have the potential to seriously endanger life and pollute the environment. Such chemicals have to be carefully managed at all time to prevent any accidental release. The successful implementation of a chemical safety programme requires co-operation from the industries to manage their hazardous chemicals properly and the support of the general public.

CODE OF PRACTICE FOR THE CONTROL OF LEGIONELLA BACTERIA IN COOLING TOWERS

CODE OF PRACTICE FOR THE CONTROL OF LEGIONELLA BACTERIA IN COOLING TOWERS

CONTENTS
FOREWORD 1
ACKNOWLEDGEMENTS 2
PART I: PRELIMINARY
1. Purpose 3
2. Scope and application 3
3. Responsibility 3
PART II: COOLING TOWERS IN BUILDINGS
4. Cooling tower design and construction 5
5. Location of cooling tower 6
6. Source of water 6
7. Discharge of water 6
8. Commissioning and operation 7
PART III: SERVICING, MAINTENANCE AND
MONITORING OF COOLING SYSTEM
9. Maintenance 8
10. Cleaning and disinfection 9
11. Water treatment 10
12. Biocide 11
13. Record keeping 12
14. Action plan for an outbreak 13
15. Water sampling and bacteriological monitoring 15
16. Enforcement action for legionella and standard plate count contamination 16
PART IV: WORKER SAFETY
17. Training 19
18. Personal Protection of workers 19
Appendices
A. Information required for the registration of cooling 21
towers
B. Allowable limits for trade effluent discharge to a 22
public sewer
C. Checklist for assessment of health risk of cooling 23
towers
D. A record of responsibility and activities to control 25
legionella bacteria in a specified cooling system
E. References 26
F. Glossary of terms 28
1
FOREWORD
Legionnaires’ disease is an acute bacterial infection of the lower respiratory
tract. Among the elderly and persons whose body resistance is weakened by other
concurrent illnesses, the infection can be fatal. The disease is caused by the inhalation
of tiny water droplets containing the legionella bacteria which thrive in poorly
maintained cooling towers. Proper maintenance of cooling towers with regular
mechanical cleaning, and routine treatment with biocides is therefore important and
necessary.
To minimise the risk of outbreaks of legionnaires’ disease in Singapore, the
Institute of Environmental Epidemiology, Ministry of the Environment, in consultation
with other government departments and professional bodies, formulated this Code of
Practice for the control of legionella bacteria in cooling towers. It is intended for
building owners/management corporations of centrally air-conditioned offices and
factories, contractors involved in the servicing and maintenance of cooling towers, and
others responsible for the design, operation and maintenance of air-conditioned
buildings.
This document specifies the design, construction and location of cooling
towers. It also provides guidelines on servicing and maintenance of cooling towers. It
includes a checklist for assessment of health risk of cooling towers and emergency
remedial measures in the event of an outbreak.
Building owners/management corporations are reminded that based on the
Environmental Public Health (Cooling Towers and Water Fountains) Regulations
2001, it is an offence to operate cooling towers that are grossly contaminated and pose
a health hazard.
WANG NAN CHEE
COMMISSIONER OF PUBLIC HEALTH
MINISTRY OF THE ENVIRONMENT
SINGAPORE
2
ACKNOWLEDGEMENTS
The advice, comments and contributions of the following departments and
professional bodies are gratefully acknowledged:
Quarantine & Epidemiology Department, Ministry of the Environment
Prosecution & Contracts Unit, Ministry of the Environment
Drainage Department, Ministry of the Environment
Environmental Health Department, Ministry of the Environment
Central Building Plan Unit, Ministry of the Environment
Sewerage Department, Ministry of the Environment
Pollution Control Department, Ministry of the Environment
Building Engineering Division, Building and Construction Authority
Department of Industrial Health, Ministry of Manpower
Medical Laboratory Board, Ministry of Health
Pathology Department, Singapore General Hospital
Singapore Association of ASHRAE Members
Singapore Institute of Architects
Institution of Engineers Singapore
Singapore Contractors Association
3
PART I
PRELIMINARY
1 Purpose
1.1 The purpose of this Code of Practice is to provide guidelines for the
prevention and control of legionella bacteria in cooling towers in order
to minimise the occurrence and risk of outbreaks of legionnaires’
disease.
2 Scope and application
2.1 This document applies to all cooling towers in new and existing
premises which are used as shops, offices, trade, business, industry or
for any other purposes in Singapore.
2.2 It is applicable for use at various stages during the inception, design,
upgrading, refurbishment, extension and maintenance of the building.
2.3 In this document, references to specific requirements under the relevant
legislations are made. Failure to comply with these requirements shall
constitute an offence under the respective regulations, and appropriate
enforcement action shall be taken.
3 Responsibility
3.1 It shall be the responsibility of the owner/management corporation of
the premises with cooling towers to:
(a) assess the risk of occurrence of legionnaires’ disease arising from
cooling towers;
(b) set up and manage a programme to minimise the risk of an
outbreak of legionnaires’ disease and monitor the effectiveness of
the programme;
(c) keep records of all activities implemented; and
(d) ensure the safety of operation and maintenance personnel and that
they are adequately trained.
4
3.2 The owner/management corporation shall ensure that persons
designated to carry out the responsibilities specified above are
competent, adequately qualified and experienced. Where the
owner/management corporation lacks the expertise, it shall be delegated
or contracted to consultants with the relevant experience and expertise.
3.3 The owner/management corporation shall ensure that every water
cooling system in the premises is registered with the Ministry of the
Environment, using the form in Appendix A.
3.4 The owner/management corporation shall ensure that there is an
instruction manual for every air-conditioning system incorporating:
(a) a schematic plan of the air-conditioning system;
(b) its operation;
(c) the necessary precautions to be taken specifying checks and their
frequency, and steps to be taken to remedy defects and deficiencies;
and
(d) equipment supplier’s particulars/contact numbers.
5
PART II
COOLING TOWERS OF BUILDINGS
4 Cooling tower design and construction
4.1 At the stage of the construction of the building and the installation of
cooling system, inspection shall be made by competent persons so that the
cooling towers pose minimal health risk to occupants of the building and
members of the public.
4.2 Cooling systems shall be designed and constructed so as to minimise the
release of drift and to aid safe operation, and regular cleaning and
disinfection.
4.3 The design of the cooling system:
(a) shall be simple and practical (deadlegs, loops and bends should be
avoided and redundant pipework removed); and
(b) shall allow for easy access to all parts of the system for inspection,
sampling, cleaning and disinfection.
4.4 A new or refitted cooling tower shall have features that minimise the
formation and release of drift, in particular:
(a) a water distribution system within the cooling tower designed to
create as little spray as possible;
(b) an effective high efficiency drift eliminator; and
(c) an enclosure of the area above the cooling tower pond. This will
reduce the effects of windage that cause the drift to escape through
the sides. It should not be transparent or translucent as sunlight can
promote the growth of algae which is conducive for the growth of
legionella bacteria.
4.5 Construction materials shall be non-corrosive, resistant to chemicals (e.g.
fibre glass, stainless steel), smooth, non-porous, opaque to sunlight and
readily disinfected. Materials used shall not support the growth and
proliferation of microorganisms.
6
4.6 A drain shall be located at the lowest point of the pond with a drain-down
valve so that the entire system can be conveniently and completely
drained.
5 Location of cooling tower
5.1 The cooling tower shall be located at least 5 metres away (measured from
the base of the cooling tower) from air circulating and ventilating inlets,
open windows and occupied areas, pedestrian thoroughfares, trafficable
areas, areas of public access, exhaust discharges from kitchens, air
handling system or other areas where nutrients conveyed from these
systems could assist in the growth of legionella.
5.2 When locating a cooling tower, the influence of adjacent buildings and of
prevailing wind direction and the wind distribution over these buildings
shall be taken into account. It shall be located away from the downwind of
air intakes for the building.
6 Source of water
6.1 The source of make-up water shall be supplied by the Public Utilities
Board water mains or any source as may be approved by the
Commissioner.
7 Discharge of water
7.1 Discharge of effluent water from cooling towers shall be into the public
sewers in accordance to the Sewerage and Drainage Act Cap. 293A.
Approval for connection to sewers shall be obtained from the Central
Building Plan Unit, Pollution Control Department, Ministry of the
Environment.
7.2 The concentration of chemicals in the effluent shall be within the allowable
limits of the Sewerage and Drainage (Trade Effluent) Regulations 1999
administered by the Pollution Control Department, Ministry of the
Environment (Appendix B).
7.3 Water from supply or condensation or other sources in the ventilation or
air-conditioning system shall be discharged into a pipe or drain
incorporating a U-bend and an air break between the condensate drain pipe
7
and the floor trap so that potentially contaminated water is prevented from
being drawn back into the ventilation or air-conditioning system.
8 Commissioning and operation
8.1 The specifications and operations of the air-conditioning system shall be in
accordance to all the provisions of the Singapore Standard Code of
Practice for Mechanical Ventilation and Air-Conditioning in Buildings (SS
CP13: 1999 or any revision thereafter).
8.2 Cooling towers shall be properly commissioned before use to ensure that
they operate correctly and safely.
8.3 The entire air-conditioning system shall be clear of any construction debris
and dirt, and cleaned before operation starts.
8.4 Precautions shall be taken to control the risks during commissioning, start
up and during the normal operation of the system.
8.5 In existing buildings:
(a) Where a cooling tower is out of use for more than five days, it shall
be drained, thoroughly cleaned and disinfected before re-use.
(b) Where a cooling tower is not in use, it shall be drained and kept dry.
8
PART III
SERVICING, MAINTENANCE AND
MONITORING OF COOLING SYSTEM
9 Maintenance
9.1 Cooling towers shall be maintained in a clean working condition and in a
good state of repair. A “good state of repair” would mean that there is no
defect in the operation, and the cooling towers should be free from
physical damage or deterioration which may arise from defects, such as,
rusty pipes.
9.2 Every system shall have a comprehensive maintenance manual that
incorporates:
(a) complete building plans of cooling and ventilation systems;
(b) cleaning methods, decontamination procedures and dismantling
instructions;
(c) procedures for water treatment; and
(d) shutdown and start-up procedures.
9.3 The regular maintenance of the cooling system shall be carried out by
competent persons, familiar with the prevention of any hazard arising from
the work.
9.4 Cooling towers shall be visually inspected at least once a week for any
physical defect, general cleanliness, organic fouling and presence of
physical debris.
9.5 A comprehensive maintenance programme including cleaning, disinfecting
and water treatment for every cooling tower shall be carried out to prevent
legionella bacteria from multiplying and to allow water treatment
chemicals to work more effectively.
9.6 Physical devices incorporating use of copper-silver ionisation, filtration,
ultraviolet light or ozone may be incorporated to complement maintenance,
but they shall not replace a proper and regular maintenance programme.
9
10 Cleaning and disinfection
10.1 Thorough cleaning, disinfection and manual desludging of cooling towers
shall be carried out at least once in six months.
10.2 Cleaning and disinfection shall also be carried out in cooling towers:
(a) that have been contaminated during construction, or by dusts or
organic matter;
(b) that have been shut down for more than five days;
(c) that have been mechanically altered or disrupted in a manner which
may lead to contamination;
(d) at regular intervals where the surrounding environment is dusty or
where the water quality is out of control; and
(e) where the adjacent cooling tower has been implicated as a source of
an outbreak of legionnaires' disease.
10.3 By-pass systems or alternating re-circulating pump systems where water is
stagnated shall be regularly cleaned and disinfected or brought into use.
10.4 The procedures for cleaning and disinfection shall be as follows:
(a) The system water shall be pre-chlorinated to achieve a measured
residual of 5 mg/litre free chlorine, to minimise health risk to
cleaning staff. Circulate water together with a biodispersant, to
enhance the effectiveness of chlorination, for 6 hours, maintaining a
minimum of 5 mg/litre free chlorine at all times. If the circuit pH
value is greater than 8, the measured residual will need to be in the
range of 15-20 mg/litre free chlorine in order to achieve the required
disinfection level. An alternative procedure to provide a more
effective use of chlorine is to introduce a heavy bleed-off for several
hours to reduce the pH of the system and its chlorine content;
(b) The circuit shall be drained and the tower, sump, and distribution
system manually cleaned. Accessible areas of the towers and its
pack shall be adequately washed. Scale and other deposits that have
not been removed shall be dissolved using chemical descalants,
carefully chosen to avoid damage to the circuit/cooling tower.
Cleaning methods which create excessive spray such as high
pressure water jetting shall be avoided. If this is not possible, the
cleaning shall be carried out when the building is unoccupied or in
the case of permanently occupied buildings, windows and air inlets
in the vicinity closed. Staff involved in water jetting shall be
10
adequately trained and wear suitable respiratory protective
equipment set out in section 18.2;
(c) The system shall be refilled with fresh water, and re-chlorinated to
maintain a minimum level of 5 mg/litre free chlorine throughout the
period of 6 hours. A biodispersant shall be used to enhance the
effectiveness of chlorination; and
(d) The system shall be drained and flushed, refilled with fresh water
and dosed with the appropriate start-up level of treatment chemicals,
including biocides.
During the procedure, the cooling tower fans should be switched off.
11 Water treatment
11.1 To control legionella bacteria, the water treatment regime shall prevent or
adequately reduce the amounts of:
(a) scale and corrosion products which might protect legionella bacteria
in the system;
(b) sediments which might prevent water treatment processes from
working effectively; and
(c) other bacteria and microorganisms.
11.2 A complete automatic water treatment shall be installed for accurate
dosing comprising:
(a) a metering pump; and
(b) a chemical dosage pot for feeding the chemicals.
11.3 Slime and algae growth shall be controlled with biocides. If there is a
sudden bloom of slime and algae, an alkaline cleaner to remove and
disperse the growth shall be applied, the system flushed, cleaned, and
biocide redosed.
11.4 The control of silt deposit shall be achieved by a chemical treatment
programme using dispersants or formulated chemicals.
11
11.5 The chemical used in the water treatment programme shall have no
detrimental effect on non-metallic materials such as rubber or epoxy anticorrosive
lining which may be used in the piping system. It shall be
compatible and neutral to the pipework materials.
11.6 No system shall be treated with any chemical or compound for which there
is no test procedure.
11.7 All packaging, storage and handling of chemicals shall be in accordance to
the manufacturer’s recommendation.
A checklist for assessment of health risk of cooling towers is shown in Appendix C.
12 Biocide
12.1 At least two (2) types of biocides shall be used alternately on a weekly
basis to prevent emergence of resistant strains of microorganisms.
12.2 Before setting up a biocidal water treatment programme, it shall be ensured
that the system is clean.
12.3 The ‘shot/slug dose’ method shall be implemented to prevent
microbiological acclimatisation. This involves the addition of the biocides,
alternating them at suitable intervals, directly into the cooling tower basin
using an automatic control system.
12.4 The biocide used to eliminate and control the growth of legionella bacteria
shall comply with the following:
(a) It shall not be a prohibited chemical in the Poisons Act Cap. 234 for
trade effluent discharge to a public sewer;
(b) It shall be effective against a wide range of micro-organisms
(including all legionella bacteria) at the recommended dilutions, and
its effectiveness supported by official independent reports;
(c) It shall be manufactured by the supplier to an independent
specification such as the British Standard 5750 or other approved
equivalent standards;
(d) It shall already have been in widespread use for similar field
application in the country of manufacture for no less than 3 years;
12
(e) It shall be proven to be effective when dosed in accordance to the
manufacturer’s recommendations (frequency, dose strength,
preparation);
(f) It shall have documentation available covering the safety and
effectiveness of the product in recirculating systems;
(g) It shall not interfere with the method used for identification of
legionella bacteria;
(h) It shall be chemically and physically compatible with processed
water and neutral to piping materials.
12.5 The chemicals used and the subsequent end-products of the treatment
programme shall be degradable with minimal hazards to the environment
in the event of accidental spillage or through draining into effluent
treatment plants, meeting all the necessary requirements of the Ministry of
the Environment under the Sewerage and Drainage (Trade Effluent)
Regulations 1999.
13 Record keeping
13.1 A formal record book for every cooling tower with accurate and adequate
information shall be kept and be made available for inspections by officials
from the Ministry of the Environment.
13.2 The record shall include:
(a) a description of the cooling tower such as location, model and
capacity;
(b) the name of the person who ensures that proper records are kept;
(c) the person or company who is responsible for the assessment of risk
and implementing and managing precautionary measures;
(d) the person or company carrying out the water treatment;
(e) details of maintenance such as:
(i) date and result of visual inspection
(ii) date of cleaning and disinfection
13
(iii) date of chemical treatment
(iv) date of biocidal treatment
(v) monitoring for
- standard plate count (date sampled and result)
- legionella bacteria count (date sampled and result)
(vi) remedial work (if required) and date executed.
Each activity (i)-(vi) shall be authenticated by signature of the person who carried out the
task.
13.3 Record books shall be kept for at least two (2) years after their last entry.
14 Action plan for an outbreak
14.1 If an outbreak of legionnaire’s disease has occurred or is suspected to have
occurred, it shall immediately be notified to:
Commissioner of Public Health
c/o Quarantine & Epidemiology Department
Ministry of the Environment
40 Scotts Road
Singapore 228231
14.2 In the event or on the suspicion of an outbreak of legionnaires' disease
implicating a cooling tower, an investigating team from the Ministry of the
Environment shall require the following under the Infectious Diseases Act
Cap. 137:
(a) a building plan showing the details of all the floors, and location of
the cooling towers and fresh air inlets to the building;
(b) the cooling tower circuit in a diagram form;
(c) the cooling tower maintenance records; and
(d) any other information required for the epidemiological investigation.
14
14.3 The implicated cooling tower shall not be drained or disinfected before
water samples are taken by the team.
14.4 The following emergency procedure shall take place urgently:
(a) cordon off the cooling tower;
(b) switch off fan of the cooling tower immediately;
(c) switch off circulation pump as soon as practical;
(d) discontinue the regular chemical treatment programme (corrosion
inhibitor, scale inhibitor) and shut off the chemical feeders; and
(e) keep all personnel clear of the tower.
14.5 The investigating team shall require the immediate cleaning and
disinfection of the implicated cooling tower, under the Environmental
Public Health (Cooling Towers and Water Fountains) Regulations 2001,
as follows:
(a) add sodium hypochlorite to the system water to obtain a measured
concentration of 50 mg/litre of free chlorine. Add a suitable
biodispersant immediately or at the same time as sodium
hypochlorite;
(b) circulate the system water with the fans off for a period of at least 6
hours, maintaining the free chlorine level at an absolute minimum of
20 mg/litre at all times;
(c) after 6 hours, dechlorinate and drain the system;
(d) undertake manual cleaning of the tower, sump and distribution
system with cleaning staff wearing suitable protective equipment as
set out in section 18.2;
(e) refill with fresh water, add sodium hypochlorite;
(f) recirculate without using fan, at 20 mg/litre of free chlorine for 6
hours;
(g) dechlorinate and drain the system;
(h) refill, recirculate, and take samples for testing; and
15
(i) re-commission the system when test results show absence of
legionella bacteria.
15 Water sampling and bacteriological monitoring
15.1 A regular testing programme for legionella bacteria (including total
bacteria count) shall be carried out to check the efficacy of the water
treatment regime at the following intervals:
Standard plate count - At least once a month.
Legionella bacteria count - At least once in every three months.
15.2 The water sample shall be taken before the dosing of biocide. If
disinfection is carried out, the water sample shall be taken no less than 3
days after disinfection to ensure effectiveness of the treatment.
15.3 The water sample shall be taken from the cooling tower pond. The systems
must be operating, and water circulated through the system for at least one
hour prior to collection of the sample.
15.4 The water sample shall not be collected:
(a) near a make-up water inlet; or
(b) with sediments that have been deliberately stirred up.
15.5 The samples shall be transported to the laboratory in a cooler with ice
packs to maintain sample temperature of 6 to 18°C within the same
working day.
15.6 The government laboratory or any laboratory conducting the tests shall
have official approval from the Commissioner/accreditation from the
Ministry of Health.
15.7 One water sample shall be taken from each cooling tower. A laboratory
report shall be supplied for each cooling circuit.
15.8 The laboratory reports shall be submitted to:
Commissioner of Public Health
c/o Environmental Health Department
16
Ministry of the Environment
40 Scotts Road
Singapore 228231
at the stipulated intervals set out in section 15.1. Each report shall be
submitted together with information on the maintenance of the system set
out in Appendix D for each cooling system.
15.9 The routine microbiological monitoring of cooling systems for legionella
bacteria shall not be used to replace sound engineering practices combined
with a regular maintenance and cleaning programme.
16 Enforcement action for legionella bacteria and standard plate count
contamination
16.1 The interpretation for various levels of legionella bacteria and standard
plate count contamination and the action to be taken by the Ministry of the
Environment under the Environmental Public Health (Cooling Towers and
Water Fountains) Regulations 2001 against the building
owner/management corporation shall be as follows:
Table 1
Legionella
bacteria count
(cfu/millilitre)
Interpretation Action
(a) <10 Maintenance
practices may not
be satisfactory
Advisory letter to rectify maintenance
programme, monitor and follow-up.
(b) >10 - <1000 Potentially
hazardous
situation
Enforcement action will be taken
under the Environmental Public
Health (Cooling Towers and Water
Fountains) Regulations 2001.
(c) ≥ 1000 Serious condition Order under Environmental Public
Health (Cooling Towers and Water
17
Fountains) Regulations 2001 to shut
down the system immediately,
decontaminate, clean and disinfect,
monitor and follow-up.
cfu = colony forming unit
Table 2
Standard
plate count
(cfu/millilitre)
Interpretation Action
(a) >100,000 Potentially
hazardous
situation
Enforcement action will be taken
under the Environmental Public
Health (Cooling Towers and Water
Fountains) Regulations 2001.
cfu = colony forming unit
16.2 The remedial measures for Table 1 (a) & (b) and Table 2 (a) above shall be
carried out not later than 24 hours after receiving the information. If
legionella bacteria are again detected, the procedures shall be repeated
until the system is free from contamination.
16.3 In the event that the advisory or warning is not heeded and subsequent
testing by the Ministry of the Environment shows that the legionella
bacteria contamination has not improved or worsened, the system shall be
shut down under the Environmental Public Health (Cooling Towers and
Water Fountains) Regulations 2001.
18
PART IV
WORKER SAFETY
17 Training
17.1 Persons carrying out maintenance and water treatment shall undergo inhouse
training to achieve an appropriate level of knowledge.
17.2 Training shall include:
(a) operations of cooling systems;
(b) principles of water treatment;
(c) maintenance of records;
(d) safety precautions; and
(e) legislations.
19
18 Personal protection of workers
18.1 All workers carrying out maintenance of cooling towers shall be informed
of the risk of legionnaires’ disease, and instructed on the proper use of
personal protective equipment.
18.2 The minimum equipment needed to protect the worker from exposure to
potential hazards according to the type of job shall be:
20
Job
Potential
hazard Personal protective equipment
Inspection Aerosol Half face respirator, capable of filtering
smaller than 5μm particulates, ordinary
work clothing.
Water treatment Aerosol,
chemical
mist
Half face respirator as above, rubber or
vinyl gloves, boots, goggles.
High pressure spraying Aerosol Half face respirator, waterproof
overalls, rubber or vinyl gloves, boots,
goggles or face shield.
Cleaning and chemical
treatment with sodium
hypochlorite solution
12%
Chemical
mist
Full face respirator with canister,
waterproof overalls, rubber or vinyl
gloves and boots.
18.3 When chemical accidentally come in contact with skin, the affected area
shall be immediately flushed with plenty of clean water.
18.4 Workers shall practise a high standard of personal hygiene. Adequate
washing facilities shall be provided and made easily accessible.
18.5 Eating, drinking and smoking shall be prohibited during maintenance
work.
18.6 Hands shall be washed and dried before eating, drinking or smoking.
18.7 Workers exposed to hazardous substances and engaged in processes listed
in sections 10 and 11 shall undergo regular health surveillance with a
medical practitioner.
18.8 In the event that the worker develops respiratory, cutaneous and other
symptoms when exposed to hazardous chemicals, immediate medical
attention shall be sought.
21
APPENDIX A
REGISTRATION OF COOLING TOWERS
1. Address of premises where
cooling towers are installed:
2. Particulars of owner of premises/management corporation of the premises:
Name:
Residential/Business address:
Telephone No.: (O) (H)
3. Number of cooling towers at the premises:
4. Particulars of each
cooling tower:
Ref No. Location
1
2
3
4
5
6
7
8
9
10
(attach a separate sheet if more than 10 cooling towers)
Submitted by: Name:
Address:
Tel No.: Date:
(an original copy shall be sent to: Commissioner of Public Health
c/o Environmental Health Department
Ministry of the Environment
40 Scotts Road
Singapore 228231)
APPENDIX B
22
ALLOWABLE LIMITS FOR TRADE EFFLUENT DISCHARGE
TO A PUBLIC SEWER
(Sewerage and Drainage (Trade Effluent) Regulations 1999)
Allowable limits
Temperature of discharge 45OC
pH value 6-9
BOD (5 days at 20OC) 400
COD 600
Total suspended solids 400 mg/L
Total dissolved solids 3,000 mg/L
Chloride (as chloride ion) 1,000 mg/L
Sulphate (as SO4) 1,000 mg/L
Sulphide (as sulphur) 1 mg/L
Cyanide (as CN) 2 mg/L
Detergents (linear alkylate sulphonate as
methylene blue active substances) 30 mg/L
Grease and oil 60 mg/L
Arsenic 5 mg/L
Barium 10 mg/L
Tin 10 mg/L
Iron (as Fe) 50 mg/L
Beryllium 5 mg/L
Boron 5 mg/L
Manganese 10 mg/L
Phenolic compounds (expressed as phenols) 0.5 mg/L
*Cadmium 1 mg/L
*Chromium (trivalent and hexavalent) 5 mg/L
*Copper 5 mg/L
*Lead 5 mg/L
*Mercury 0.5 mg/L
*Nickel 10 mg/L
*Selenium 10 mg/L
*Silver 5 mg/L
*Zinc 10 mg/L
*Total metal 10 mg/L
* where two or more of the metals are present, the
concentration in the trade effluent shall not exceed 10 mg/L.
APPENDIX C
23
CHECKLIST FOR ASSESSMENT OF HEALTH RISK OF
COOLING TOWERS
(A separate form shall be used for each cooling tower)
Site address: …………………………………………………………………………..
Reference number of cooling tower: ….……..
1 Registration
1.1 Is the cooling tower registered with Ministry of the Environment? (YES)
2 Water supply and discharge
2.1 Is the water supply from PUB or approved by Commissioner? (YES)
2.2 Is the effluent discharged into a public sewer? (YES)
3 Location
3.1 Is the cooling tower located in a position:
(a) that is near a fresh-air intake to an air-conditioning or ventilating
system?
(NO)
(b) that it is possible for wind to carry the sprays/aerosols into the
windows of an adjacent building?
(NO)
4 Record keeping
4.1 Is there a record/logbook for inspection by Ministry of the Environment? (YES)
5 Cooling tower
5.1 Are all parts of the cooling tower accessible for maintenance? (YES)
5.2 Is there an accessible sampling point at:
(a) cooling tower pond? (YES)
(b) bleeding point? (YES)
5.3 Is the pack:
(a) made from natural materials e.g. wood?
(b) clean/scale free/no slime?
(c) easily cleaned and disinfected?
(NO)
(YES)
(YES)
5.4 Are natural rubbers used as seals or caskets? (NO)
5.5 Is the aerosol creation low? (YES)
24
5.6 When the system is operating at full load, is there excessive
drift from the cooling tower discharge?
(NO)
5.7 Are there drift eliminators? (YES)
Are they securely and firmly fitted? (YES)
6 Maintenance
6.1 Is there a regular maintenance programme in operation? (YES)
6.2 Is the cooling tower and the entire distribution system cleaned
and disinfected at least once every six months.
(YES)
7 Water treatment
7.1 Is there a water treatment programme to control:
(a) scale?
(b) slime?
(c) corrosion?
(d) sludge/algae?
(e) microorganisms (including legionella bacteria)?
(YES)
(YES)
(YES)
(YES)
(YES)
7.2 Are the following apparent within the cooling tower:
(a) corrosion?
(b) fouling?
(c) debris, foam, sludge or slime?
(NO)
(NO)
(NO)
7.3 Is the cooling water clear/clean, without silt/scum/foam? (YES)
8 Monitoring
8.1 Is there a regular water treatment for monitoring? (YES)
8.2 Are standard plate counts high (>100,000 cfu/ml)? (NO)
8.3 Are legionella bacteria detected in the system (>10 cfu/ml)? (NO)
8.4 Are the results of bacteriological monitoring routinely
conveyed to Ministry of the Environment?
(YES)
( ) correct answer in bracket
Assessed by: Name:
Address:
Tel. No.: Date:
APPENDIX D
A RECORD OF RESPONSIBILITIES AND ACTIVITIES TO CONTROL
LEGIONELLA BACTERIA IN A SPECIFIED COOLING SYSTEM
25
1. Building: Name:
Address:
Ownership: Government/Statutory Board/Private*
2. Building owner/manager: Name:
Address:
3. Location/Ref. No. of cooling tower:
4. Maintenance contractor: Name:
Address:
5. Water treatment specialist: Name:
Address:
6. Previous cleaning and disinfection: Date:
7. Biocidal treatment for legionella:
(a) Name of biocides: 1.
2.
(b) Schedule of treatment: Continuous/slug or shot* dose method
(c) If slug/shot dose method is used,
date of previous treatment: Date:
8. Water sampling for legionella bacteria test: Date:
9. Laboratory report submitted by: Name:
Company:
Tel No.: Date:
* delete where necessary
26
APPENDIX E
REFERENCES
1. National Health Service Estates, UK. Health Technical Memorandum 2040.
The Control of Legionellae in Healthcare Premises - a Code of Practice, 1993.
2. Health and Safety Commission, UK. The Prevention or Control of Legionellosis
(including Legionnaires’ Disease) - Approved Code of Practice, 1995.
3. Health and Safety Commission, UK. Control of Substance Hazardous to Health
Regulations - Approved Codes of Practice, 1994.
4. Health and Safety Commission, UK. The Control of Legionellosis including
Legionnaires’ Disease, 1993.
5. The Chartered Institution of Building Services Engineers, UK. Technical
Memoranda TM13: 1991. Minimising the Risk of Legionnaires’ Disease, 1991.
6. The Industrial Water Society, UK. Cooling Water Treatment - a Code of
Practice, 1994.
7. The Industrial Water Society, UK. Guide to Risk Assessment for Water
Services, 1994.
8. Department of Health. Report of the Expert Advisory Committee on Biocides,
1989.
9. Department of Employment, UK. Health and Safety - the Notification of
Cooling Towers and Evaporative Condensers Regulations, 1992.
10. British Association for Chemical Specialities, UK. A Code of Practice - the
Control of Legionellae by the Safe and Effective Operation of Cooling Systems,
1989.
11. Council of Standards Australia. Control of Microbial Growth in Air Handling
and Water Systems in Buildings, 1992.
12. Standards Association of Australia. Australian Standard. Air-handling and
Water Systems of Buildings - Microbial Control (AS 3666), 1989.
27
13. New South Wales Health Department, Australia. Code of Practice for the
Control of Legionnaires’ Disease.
14. World Health Organisation. Epidemiology, Prevention and Control of
Legionellosis; Memorandum from a WHO meeting. Bulletin of the World
Health Organisation, 1990; 68: 155-64.
28
APPENDIX F
GLOSSARY OF TERMS
Aerosol A suspension in gaseous medium of solid particles, liquid particles
or solid and liquid particles having negligible falling velocity.
Airconditioning
A form of air treatment whereby temperature, humidity, ventilation
and air cleanliness are all controlled within limits determined by the
requirements of the air-conditioned enclosure.
Air intake Any opening through which air is admitted to an air-handling system
in a building.
Algae Small, usually aquatic plants which require light to grow.
Biocide A chemical capable of killing living microorganisms.
Bleed Water deliberately removed from a cooling system to control the
concentration factor of dissolved solids.
Clean Visually free of sludge, slime, algae, fungi, rust, scale, dust, dirt and
any foreign material.
Competent
person
One who is adequately qualified and experienced to provide
supervision for the operation and maintenance of cooling towers.
Cooling tower Any device in which atmospheric air is passed through sprayed water
in order to lower the temperature of the water by evaporative cooling.
Corrosion
inhibitors
Chemicals designed to prevent or slow down the waterside corrosion
of metals.
Deadleg A length of pipe, normally closed at one end, or ending at a fitting.
Disinfection Reduction of population of micro-organisms using chemical or
physical means.
Dispersant A chemical usually added with other treatment chemicals to loosen
organic material adhering to surfaces and prevent accumulation of
sludges.
Drift The water aerosol which emerges from the airflow outlet of a cooling
tower.
29
Drift eliminator Equipment containing a complex system of baffles designed to
remove water droplets from cooling tower air passing through it.
Filtration The process of separating solids from a liquid by means of a filter
media through which only the liquid passes.
Fouling Organic growth or other deposits on heat transfer surfaces causing
loss of efficiency.
Legionella A genus of bacterium which is ubiquitous in aqueous environments
and found in water systems in the built environment, including
cooling systems that are not properly or regularly maintained. It
comprises numerous species. Legionella pneumophila is the most
common causative organism of legionnaires’ disease.
Legionnaires’
disease
A rare form of severe pneumonia caused by Legionella pneumophila.
It affects principally older men, especially smokers or persons whose
defences are already impaired by serious disease.
Make-up water Fresh water added to circulating water to compensate for losses, by
evaporation, bleed, drift or leakage.
Outbreak Two or more cases of legionnaires’disease linked by time and place.
Premises All non-domestic premises used for or in connection with trade,
business or other undertaking.
Scale inhibitor Chemical added to water to inhibit formation of scale.
Slime A mucous-like material which is produced as part of an organism’s
metabolism and allows adherence of protective layer to surfaces.
Sludge A general term for soft mud-like deposits on heat-transfer surfaces or
other important sections of a cooling system.
Windage Physical loss of water from the base of a cooling tower caused by
wind of unusual pattern passing through it.

Refer to NEA website for the latest update.