Designing, Operating Safe HVAC Systems for Hazardous Spaces

From ASHRAE Journal Newsletter, August 10, 2021

In some cases, HVAC system design is a matter of life and death.

Hazardous spaces are defined as rooms or buildings in areas with potential or continuous concentrations of flammable, ignitable, corrosive or toxic substances. A designer must determine what those substances are and then decide what types of equipment to design and install and how the equipment should be operated and maintained to mitigate all potential life-safety risks, according to Mike Baucom, Member ASHRAE, member of TC 9.2, Industrial Air Conditioning Subcommittee for Hazardous Spaces.

“In many cases, an HVAC system must be specially built and use a combination of explosion proof, intrinsically safe and non-incindive equipment to address flammable or ignitable substances, and it may also require integrated chemical filtration systems to prevent corrosive and toxic substances from being recirculated or introduced to a room or building from what would otherwise be considered as a fresh air or make-up air source,” said Baucom, who wrote the recently released ASHRAE Guide for HVAC in Hazardous Spaces.

The guide is the first publication on this subject in the U.S., written to educate designers, engineers and installers and ensure that HVAC equipment of this nature is installed in a proper manner, said Baucom. Due to this guide’s particular emphasis on toxic chemicals, asphyxiants, flammable gases and combustible dusts, designers, engineers and technicians can use the guide as an ideal resource when designing, installing, operating and maintaining safe and effective heating, ventilation, pressurization, dilution, filtration and air-conditioning systems for hazardous spaces. The guide provides candid overview and “best practice” perspectives and also cites or refers to many published recommendations and standards from America’s most recognized safety authorities, he said.

“The guide steps readers through a detailed series of considerations to satisfy critical safety parameters as established by numerous standards and recommended practices. Those considerations include identifying the types and sources of hazardous substances, selecting a protection system, designing protected spaces, selecting equipment and best practices for installation, operation and maintenance of these critical systems,” he said.

The guide points engineers to where they can find essential and authoritative requirements and recommendations, how to identify and mitigate the hazards they must overcome, what protection methods are available to address those hazards and how to effectively design, install and maintain spaces and the related HVAC equipment in question, said Baucom.

“The core goal of this guide is to prevent or minimize the occurrence of injuries and catastrophic events and save lives, as new facilities for oil and chemical manufacturing rise and older facilities are expanded and renovated,” said Erich Binder, Life Member ASHRAE, chair of TC 9.2, Industrial Air Conditioning and Ventilation Committee.