Piping Risks in Fires

During structure fires and wildfires, piping impacts the safety of buildings and communities. When not properly installed, combustible piping can cause firestop failures, allowing flames and smoke to spread through walls and floors. 

In addition, piping materials such as PVC and PEX emit harmful chemicals when they get overheated, melt, or burn. Benzene released into plumbing systems from plastic pipes can poison water for structures not directly affected by a fire, forcing entire communities to find alternate sources of potable water. In extreme situations, the higher fire temperatures and toxic smoke from plastics like those in many plumbing systems, carpets, floors, and furnishings can turn a serious fire into a deadly one. Over the long term, even low levels of exposure to toxins released during fires puts firefighters’ health at risk. 

Toxic Smoke: Testing shows that burning plastic pipes, such as PVC, emit harmful gases such as carbon monoxide, hydrogen bromide, hydrogen chloride, hydrogen cyanide, nitrogen oxide, and sulphur dioxide, among others. Even at low levels, such gases can overwhelm building occupants and the first responders who come to fight the fire. 

Firestopping: Homes, schools, and workplaces with plastic pipes should be designed to mitigate increased risks of direct structural failures. Plastic is an intumescent material that can expand “up to 35 times” its initial volume in the event of a fire, according to plumbing and firestopping experts at HoldRite. Designing firestops to resist such expansion requires significant expertise, which is often not well understood by either mechanical contractors or even building inspectors. Failed firestops will allow fire, smoke, and gases to penetrate through walls and floors.

Chemical Releases: Burned and melting pipes can also threaten the safety of communities’ water infrastructure. The Camp Fire in Paradise, CA, damaged plastic water supply and distribution pipes, introducing benzene and methylene chloride into water supplies that subsequently became highly contaminated. Until the town’s piping infrastructure could be replaced, Paradise residents had no access to safe tap water.

Recommendations

Building owners and design teams tasked with building (or rebuilding) structures at risk of fire should incorporate piping in their design and construction planning. This may require adding a firestopping expert to the project to ensure proper materials and installation methods are used.   

In the wider community, officials and water systems experts should also assess the risk of large-scale fire events such as wildfires. Areas that use plastic for significant portions of their piping infrastructure should plan to test for benzine and other toxic chemicals after a fire, and have contingencies for replacing plastic pipes with noncombustible materials such as iron, steel, and copper. They should also create plans to communicate with residents on risks, so they know not to drink or bathe in contaminated water. Leaders may also need to provide residents with alternate sources of water for a period of months after a fire. 

“Codes Must Be Responsive to Current and Future Hazards,” by Jay Peters of Codes and Standards International and the International Association of Plumbing and Mechanical Officials, details the safety hazards that plastic piping presents and calls for changes in building codes that reflect those dangers. Included in the White Paper below is a joint statement from the International Association of Fire Fighters and the United Association of Plumbers, Fitters, Welders and Service Techs that calls for an all-out ban on plastic piping in critical care-facilities.

Related Articles

Chemical Leaching from Plastic Pipes

Andrew Whelton’s latest study confirms that plastic drinking water pipes release benzene and other volatile organic compounds (VOCs) into the water supply when exposed to extreme heat. … more