As part of Singapore Green Plan 2030 to quadruple solar energy deployment by 2025, large-scale deployment of solar photovoltaic systems is expected. In view of the hazards/risks associated with the activity of installation of solar photovoltaic systems at height such as falling from height, companies need to address WSH risks to ensure workers can install such system safely
Introduction
Under the Singapore Green Plan 2030, Singapore aims to have cleaner and better use of energy and become more energy efficient. One of the targets is to quadruple solar energy deployment by 2025, including covering HDB roof tops with solar panels, so that by 2030, solar energy deployed will be five times that of today. At its peak, the solar energy generated can power about 350,000 households a year.
This means that large-scale deployment of solar photovoltaic (PV) systems across the island is expected in the years ahead.
The best place for solar PV systems to be installed in land-scarce Singapore is on the roofs of commercial and residential buildings. Hence, rooftops will become a typical workplace setting and demand for competent contractors to complete these installation works will rise accordingly.
In view of the upcoming demand, companies should take the following into consideration to ensure companies and workers can work safely.
Pre-installation of the Solar PV system
The first step is to select the right solar installer and roof work contractor (if engaged). Ensure that both have the sufficient knowledge, qualifications, equipment, skills, and safe systems of work that comply with the WSH legislations.
The solar installer and roof work contractor must perform the following checks before starting onsite installation of the solar PV system: • Survey the actual worksite, i.e. the roof and surroundings; • Conduct worksite-specific risk assessment, such as inspecting the roof for structural integrity issues such as sharp edges, rot, or a sagging roof; • Assess the slope and pitch of the roof to evaluate the risk controls needed to ensure the safety of workers and the stability of the equipment used; and • Implement appropriate risk controls, such as temporary edge protection, scaffolding, mobile elevating work platforms, exclusion zones, and access to the roof or mechanical lifting aids.
Installation of the Solar PV System
The solar installer must survey the actual worksite to determine that the roof is suitable and safe for the installation. Critical checks for suitability include:
- Confirming that the roof can support the additional loading imposed by the solar PV system, as well as the workers and their equipment;
- Checking that there are no open sides or whether it is possible to install edge protection at all open sides and openings;
- Inspecting the roof condition and making the necessary repairs before allowing installation works to begin;
- Ensuring there is sufficient space to be allocated as designated accessways between solar panel groups;
- Verifying that designated accessways are free of hazards e.g. fragile surfaces.
- Installing systems at safe distance from fall and electrical hazards, and allowing for a safe means of access, where reasonably practicable.
Maintenance of the Solar PV System
To eliminate or minimise the risks during the maintenance phase of an installed solar PV system, solar installers are recommended to consider the following:
- Select a solar PV system that requires low or no maintenance alternatives where available, for example plastic wire ties would require replacement whereas coated metal ones may not
- Select a modular system with removable panels and components for easy replacement;
- Install a remote monitoring and control system to reduce the need for rooftop visits;
- Deploy drones for site inspection;
- Ensure that sufficient space has been allocated for maintenance equipment and onsite activities;
- Label and mark all electrical components properly; and
- Design a system to facilitate the isolation of individual panels
Hazards Arising from Installation and Maintenance of Solar PV Systems Installing and maintaining solar PV systems expose workers to risks of serious injury or death. The following are the hazards that workers may face:
Access risks
Getting to the roof may be a challenge depending on the building type and site conditions. Ideally, the building should be equipped with proper staircases or an elevator to provide direct access to the roof. Some buildings offer a fixed ladder with access via a roof hatch. If these are not available, an erection of a tower scaffold is necessary for safe access to the roof.
Fall from height
Working on roofs and other works at height carry the risk of falling from height. Solar installers and contractors must put in place measures to ensure workers always remain safe while at work A site-specific fall prevention plan (FPP) must be established and implemented to eliminate or mitigate the risk of falling from height. Workers have a responsibility to comply with the safety requirements and report unsafe situations to their employers. Where there is a risk of objects falling from the roof, protective barriers must be installed to prevent objects from injuring anyone below.
The site-specific FPP must cover the following
• Permit-to-Work (PTW) system;
Put in place a PTW system for work activities where a person could fall more than three metres. Ensure on-site checks are carried out by a competent person and risk controls are confirmed effective before authorising the work at height Details on PTW system, including a sample PTW template can be found in the Code of Practice for Working Safely at Heights.
• Safe Work Procedures (SWP)
:Develop a SWP for carrying out the task on the roof, taking into account the roofs characteristics, e.g. material of construction, profile and angle of slope, and the duration and frequency of work Provide supervision to ensure the SWP is strictly followed. A comprehensive SWP for work on roofs can be found in the WSH Guidelines on Working safely on roofs
•Open side guarding:
Install temporary guardrails or erect a scaffold platform with guardrails, if feasible, to prevent workers from falling off the roof edge. If this is not feasible, install a properly anchored lifeline for workers to attach themselves to, using fall-arrest or travel-restraint equipment.
• Worker training:
Deploy only workers who have successfully completed the Workforce Skills Qualifications (WSQ) Perform Work at Height course to work on roofs. Train workers to always anchor their safety harnesses when working at height.
• Personal Protective Equipment (PPE):
Equip roof workers with anti-slip safety footwear and, if necessary, fall-arrestor travel-restraint equipment along with secure anchor point(s) or lifeline. Read more in the WSH Guidelines on PPE for Work at Heights.
If there is a risk of falling through a fragile surface while on the roof, e.g. skylights, additional risk controls may include:
- Identify, mark, barricade and communicate the presence of fragile surfaces;
- Cover the fragile surface with a secure cover or provide all-round barricades;
- Provide workers with a way to work under, e.g. using a tower scaffold, or above the fragile surface, e.g. using a mobile elevated work platform;
- Install roof ladders, gangways, crawl boards and roof brackets to facilitate movement on sloping roofs; and
- Deploy safety nets below fragile surfaces.
Electrical risks
Solar panel installers and maintenance personnel may be exposed to electrical risks while at work. To prevent electrical injuries, companies are advised to carry out the following: • Deploy only workers trained for electrical work; • Implement a PTW system for electrical works and allow work to start only when electrical systems are de-energised or isolated;
• Implement lockout-tagout procedures to ensure de-energised or isolated systems cannot be turned on by accident; • Test if the electrical equipment is dead, e.g. by using a voltage detector, before working with it; • Provide workers with insulated tools, rubber-soled shoes, and electrically resistant gloves; • Stop electrical work during unfavourable weather, e.g. when there is a lightning risk, or when the work area is wet and • Ground all electrical circuits before turning on electrical systems.
Other risks
Monitor weather conditions and stop any roof works during unfavourable weather conditions such as strong winds, lightning, and heavy rain. For strong winds, ensure all equipment used are secured to prevent them from being blown off the roof.
Check for slippery surfaces, e.g. wet or mossy conditions, as they may pose a risk to slips and falls; use anti-slip footwear if necessary. Work zone(s) need to be kept clear of tripping hazards such as loose tools, cables, or debris.
Take care of workers by providing rest breaks, access to cool water, and mechanical aids, e.g. trolleys and power tools, to manage fatigue and heat stress.
Further information
Annex 1:
WSH Checklist for safe installation of solar PV systems on the roofs
This checklist highlights the key WSH considerations for installation of solar PV systems on roofs to help solar installers and contractors better manage WSH and implement effective control measures. The checklist is by no means exhaustive and is not a replacement for proper planning including a fall prevention plan and risk assessment
