Heat generally trails heights in the hierarchy of workplace hazards that window cleaners encounter, but this summer has many employers refreshing the hot weather plans that Ontario Ministry of Labour investigators would look for if they were ever called to a work site. That’s a matter of stating the criteria — usually threshold humidex readings and/or smog alerts — that would then trigger the plan’s documented steps for reducing workers’ vulnerability to heat stress.

Under Ontario’s Occupational Health and Safety Act, employers are required to take every reasonable precaution to protect their workers, including, as the Act spells out, “developing policies and procedures to protect workers in environments that are hot because of hot processes and/or weather”. The referenced standard from the American Conference of Governmental Industrial Hygienists (ACGIH) has a goal to maintain a core body temperature no higher than 38 degrees Celsius, or one degree Celsius higher than what’s considered normal.

Workplace health and safety practitioners advise that measures to safeguard building services personnel could include: adjusting working hours to cooler times of the day; working in the shade when possible; extra rest periods; and ensuring they drink water even if they don’t feel thirsty. Complementing the last point, workers should be trained to recognize the symptoms of heat stress, both personally or if they need to assist a co-worker.

Dual-directional risks for window cleaners

“The dilemma on a swing stage is: where do you go to rest? Do you need to bring it all the way down to ground level?” says Warren Clements, an occupational hygiene specialist with Workplace Safety & Prevention Services. “The other challenge is that you’re wearing fall protection so that adds some additional weight.”

Especially on glass facade buildings, window cleaners are subject to heat from two directions as the sun beats down from above and reflects back from the building surface. Since glass facades are designed to deflect much of the solar load, that surface can become very hot.

“It is quite possible, under the right conditions, that the temperature of the glass could rise by as much as 40 to 50 degrees Celsius,” says Hitesh Doshi, an engineer and professor in Ryerson University’s Department of Architectural Science. “The good thing is that the sun moves during the day so it’s not a permanent condition. You can work around it. If possible, start somewhere where the site is in the shade and move with it.”

Perhaps for this reason, Clements — who frequently consults in very hot workplaces such as foundries, bakeries and sites using industrial ovens for drying processes — reports that neither he nor other colleagues specializing in heat stress exposures assessments have ever been called on to study impacts on workers on glass facades. In keeping with standard health and safety practices, he emphasizes the importance of eye protection to mitigate reflected light and sunscreen to protect from sun exposure.

“If you use sunscreen, you don’t get burned,” he says. “If you work Monday to Friday, and your skin gets burnt Monday, you just don’t have much time to recover from the burn.”

Acclimatization takes time, dissipates quickly

Few building services personnel would be categorized as acclimatized, meaning that their bodies have adapted to higher levels of heat after sustained exposure. Guidance from the Canadian Centre for Occupational Health & Safety estimates this should happen after six or seven consecutive days of experiencing such temperatures and, historically at least, intense heat waves rarely last this long. Even if achieved, acclimatization can dissipate within a few days so employers should consider that when scheduling tasks following a long weekend or supervising workers returning from vacation.

Maintenance and service calls on heat-absorbing rooftops can be an intense experience, and working conditions can be even more uncomfortable inside an enclosure around HVAC equipment. “It can be just like a black asphalt driveway, depending on the roofing materials. If there are barriers or enclosures, they will cut off the wind, which eliminates a source of cooling,” Clements observes.

Rooftops also make a more significant contribution to the city’s sweltering ambience. “The heat island effect primarily arises from the sun heating up materials on horizontal surfaces. At the hottest time of the day, when the sun is directly overhead, it is perpendicular to the cladding materials (on the facade) so cladding really doesn’t impact the heat island effect as much as the roof element,” Doshi explains.

Proof of Diligence

If workers are alone on a jobsite, it will be even more important to check in on them regularly. Clements suggests hot weather plans should explicitly state how that will be done — i.e. via cell phone — and at what intervals.

For their part, building owners/managers should ask contractors for proof of hot weather plans as part of compliance due diligence. They will also need to have their own hot weather plans for in-house operations and maintenance staff.

Beyond that, for buildings with WELL certification, optional optimization features could apply. One of those is an emergency preparedness plan, which entails a comprehensive strategy for responding to a range of potential situations, including heat waves. The other is provision of community space to support diversity and public engagement.

“In the event of extreme heat, the public space can be turned into a cooling centre to provide the community, including building service providers, with access to a cooler environment,” suggests Kimberley Glassford, a senior sustainability consultant with Premier Environmental Services.

Barbara Carss is editor-in-chief of Canadian Property Management.