Ongoing population growth and urban sprawl are driving housing development into areas that were once home to wildlife and forests, expanding what is known as the Wildland Urban Interface (WUI). WUI areas are where the built environment and wildfire-prone vegetation/forested areas meet, and approximately 8 million homes in WUI designated areas were built in the United States from 1990 to 2010. Though the pace of construction slowed from 2010 to 2020, the decade still saw the construction of 2.6 million new homes in WUI areas.

Given the increasing number of homes in close proximity to wildfire-prone areas, the increase in wildfire frequency, and the predicted extension of the fire season, there is increased consumer demand for enhanced fire resiliency in WUI areas and improved resilience to smoke events like those that overwhelmed much of North America last year. As this blog will explain, improving resiliency to both wildfires and excessive smoke goes hand in hand with improving a building’s energy efficiency.

Specifically, we’ll explore:

·         The difference between active and passive systems.

·         Passive House principles and building envelopes.

·         Passive House principles and efficiency.

·         Passive House principles and fire safety.

·         How Partel’s line of advanced fire-rated membranes can improve energy efficiency and fire safety.

Active and Passive Systems

Fire safety and energy efficiency seem like two vital but distinct considerations when designing and constructing a building, especially when one speaks of active systems. Active systems can be thought of as systems that require either an automated or manual system to operate. With respect to fire safety, this may include fire extinguishers, sprinkler systems, or even smoke alarms. Meanwhile, active energy efficiency measures typically revolve around innovative technologies that help to automate mechanical systems and optimize energy use.

As the name suggests, passive systems are more or less stationary. They are built into the very fabric of the building. Within the world of fire safety, passive systems may include the inclusion of fire-resistant building materials to prevent fire penetration; simplifying the form factor of a building to mitigate the risk from firebrands; or improved air sealing and enhanced filtration for mechanical systems to keep out smoke.

Passive House Principles and Efficiency

Using high-performance windows and doors while making buildings extremely airtight and well-insulated ensures that the conditioned spaces within the building envelope can be cooled and heated with minimal energy use—often with no more than onsite renewable sources of energy. Mechanical ventilation provides a steady supply of fresh air, while heat recovery further minimizes energy use, as the outgoing exhaust air conditions the incoming fresh air. Thermal-bridge-free detailing further enhances performance while also preventing the buildup of condensation, which can lead to mold growth. When these five principles act in concert, the result is a home that is not only efficient and durable, but remarkably comfortable.

Passive House Principles and Fire Resilience

Passive principles not only create more efficient and healthier buildings; they also create buildings that are resilient in the face of smoke events and fires. As alluded to above, the conscientious design decisions that are made to eliminate thermal-bridging lead to simplified form factors, which not only reduces the surface area of the structure but gives embers fewer points of entry. Meanwhile, a combination of airtight construction and high-performance windows will keep smoke and particulate matter from penetrating the building’s envelope, while a combination of mechanical ventilation and air filtration will ensure that only fresh air is admitted into the home.

Partel’s EXOPERM Line

Project teams have to balance a lot of factors when deciding on materials choices, even when they are building to Passive House standards—fire safety is only one of them. Additional considerations may include costs, aesthetics, performance, and more climate- or site-specific factors that can influence how the envelope is assembled. For example, a wall that is designed for a hot and humid climate like New Orleans is going to have a dramatically different wall assembly from a temperate and humid climate like Vancouver.

Partel’s line of EXOPERM membranes, including EXOPERM MONO DURO 200 and EXOPERM MONO 250 SA, offers builders a range of performance metrics while providing exceptional durability and fire resilience. Meanwhile, Partel’s numerous tapes, including their VARA and CONEXO lines, complement these membranes to enhance overall building performance.

EXOPERM MONO DURO 200

Partel’s EXPOERM MONO DURO 200 is a diffusion permeable polyurethane membrane that is installed on the cold side of insulation and is suitable for façade walls, roofs, and decking underlays. It is highly vapor open with an Sd value of 0.12m and an air permeance value of 0.01m³/(m²h), as well as a fire classification of B-s1, d0, according to EN13501-1, meaning it has limited combustibility and only marginally contributes to fire spread; that it produces minimal smoke in the event of combustion; and that it does not produce any flaming droplets or particles in the event of a fire.

Conclusion

Passive House principles are not just about energy efficiency and comfort. They can also create buildings that are more resilient in the face of wildfires and extreme smoke events. These principles are also amenable to a variety of climates, especially when project teams have access to a suite of high-performance components like those offered by Partel.

To learn more about Partel and their numerous brands of membranes, tapes, and accessories, you can visit their site here.