Safely Working on Green Roofs

Photo: NLSM/Greg Van Riel

Fall accidents, injuries, and deaths happen in the workplace, every year. According to Occupational Healthy and Safety (OHS) Canada, more than 40,000 workers get hurt each year because of falls. These accidents are a result of poor safety practices, failure to set up proper protective equipment and lack of training.

Green roof workers often need to get close to the edge of the roof. Protecting installers and maintenance crews on a green roof is not an option. It is a necessity and required by law. The Canadian Centre for Occupational Health and Safety (CCOHS) provides a list of legislation from across Canada that requires very specific fall protection measures in addition to personal protective equipment (PPE). Let’s read how to keep everyone safe on a green roof.

Fall Prevention is Key

While the employer and workers are required to take the necessary steps to reduce risk, fall prevention starts with the designer.

Good Design – Getting it Right From the Start

Safe design of a structure is critical to reduce or eliminate fall hazards during the construction phase, and for the routine maintenance that follows. Maintenance requirements for green roofs should be planned for at the design stage, and provision needs to be made for safety systems so that work can be carried out safely. If possible, a walkout is ideal for roofs that require regular access. Otherwise, safe access points are very important as are footpaths and walkways for maintenance crews.  Additionally, all green roofs from a height of 2.4 metres (8 feet) and higher should have fall prevention and fall arrest systems designed at the start to ensure rooftop safety for all.

 

Guardrails on Sherway Gardens’s green roof, Toronto, Canada.

Basic Types of Fall Protection 

1) Control zone

A control zone is the interior safe area created with a temporary warning line (bump line) at least 2 metres from the unprotected edge of a roof. This is ideal when the green roof area is within the provided control zone. This is mostly used during the construction phase as it would be impractical to set up for each maintenance visit.

2) Guardrails

Guardrails are an excellent method of fall prevention because they put a barrier between people on the roof and the unprotected edge. There are two types: temporary and permanent. Temporary guardrails are often used during the construction period.  Permanent free-standing safety guardrails, as in image shown above on the Sherway Gardens green roof, are used for ongoing maintenance visits.

 

3) Travel-restraint system

Travel restraint lifeline on the Yonge Sheppard Centre green roof, Toronto, Canada.

A travel-restraint system keeps you from getting too close to an unprotected edge. There are two types of travel-restraint systems: fixed (attached) and ballasted (free standing). Ballasted is ideal in retrofit green roofs or when fixed roof anchors are not feasible. For information on ballasted anchors, contact NLSM.

The system works in combination with a worker’s PPE which is used to tie off to the lifeline. Workers must be trained and certified in Working at Heights / Fall Protection. This system works well during the construction phase and on ongoing maintenance visits.

 

Fall-restriction ladder safety system by MSDirect.com.

4) Fall-restriction system

Vertical wall-mounted ladders are a popular mode

of access for many green roofs. A vertical lifeline system greatly reduces the free-fall distance as the worker is connected by their PPE. This system works well during the construction phase and for ongoing maintenance visits.

 

5) Fall-arrest system

Fall-arrest anchors on 4 The Kingsway. Photo NLSM/Greg Van Riel

A fall-arrest system is used when other means of fall prevention and fall-restriction are not possible.

Fall-arrest keeps you from making contact after you have fallen. Workers must be instructed in how their PPE connects to the anchor and how to use the fall protection system.

All the systems above and PPE equipment should be approved by the Canadian Standards Association (CSA).

 

NLSM’s team at Working at Heights Training. From left Sasha Aguilera, Sawsan Hlal, James Weldon and Alex Mozhzhukhina.

Worker Training: Keep Everyone Safe & Smiling

In addition to a safe, well-designed rooftop, regardless of the province in which they operate, employers must assess their roof safety plan and provide workers with Working at Heights / Fall Protection training. Employees must also take the necessary steps to reduce risk and be accountable for their own safety.

Canadian Centre for Occupational Health and Safety recommends working at heights safety training for employers, managers, and supervisors, including those who manage contractors. Working at heights certification is a mandatory requirement in many jurisdictions.

All fall prevention equipment should be approved by the Canadian Standards Association (CSA).


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NLSM is Canada’s leading supplier of pre-vegetated roofs such as LiteN’Less™, Xeroflor® and StormCap™ systems. We customize to local requirements. Offer warranty& maintenance support, provide ​stormwater calculations specific to location ​and building/roof type, stormwater test data & related innovative hydrologic modeling. Email or call (416) 637-5772 Ext 1.