As modern society strives to go Green and be more conservation orientated, the fire service as we know it is slowly changing without much attention to that industry.
As many municipalities within the State of Nevada are adopting the ICC Green Construction Code, many visible changes are occurring such as more solar photovoltaic systems, wind-energy systems, and permanent shade projections. Many changes that cannot be seen are also occurring and play a role in our fire suppression efforts such as low emissivity windows, bio-based materials, and construction of the building thermal envelope. While many articles have been composed of the hazards to firefighters with renewable energy systems and even residential fire sprinklers, I will focus more on the construction of the building itself and the new hazards and benefits we gain with current ICC Green Code construction and Energy Conservation Code. While these are just a small portion of construction requirements and methods in current green construction practices, they are definitely notable hazards for fire service personnel.
Let’s first take a look at an obvious feature of new homes as well as commercial buildings, fenestration. Yes, it is a very fancy word for glass. In the International Energy Conservation code, we started to see a greater demand for glass. More windows, more skylights, orientation of the glass and shading of the glass were all addressed by the ICC. Now minimum standards were established for the amount of glass you must have to provide more natural light. The standards are prescriptive, but push for more and more “daylighting,” so more glass. Not just any glass will do for green buildings, though, you must utilize an approved high-efficiency window.
Low-emissivity windows (low-e) have made an increased appearance in most construction conducted within the last 10 years. They provide a more easily climate-controlled atmosphere within the structure and greatly reduce the effects of ultraviolet rays entering the home. While a home or business owner the has the option for low-e windows that can save money in heating and cooling costs, one side effect of these windows is fire. Don’t let this sway you from making your home or community more energy efficient, simply understand that fires can be created by low-e windows.
Numerous reports of fires throughout the United States have been reported to have been caused by low-e windows. These fires are generally started on lawn furniture, fences, siding, garbage cans, and other exterior items of the home. This reflected energy off of low-e windows is nothing new to departments such as the Lincoln (CA) Fire Department who have responded to a number of these fires and incidents of damaged landscaping and garbage cans. While California has been in a recent drought, this form of ignition has been exacerbated by the presence of artificial grass and dry vegetation around the homes. While most of the times fire ignition is not present, it is still a concern for the fire service. These windows are highly reflective and it is because of this property we see fires occurring to the exterior of the building. Much like the principle of a magnifying glass, any concave surface on the window can provide reflected radiant heat in a condensed form. Currently, there are new protective coatings being applied to low-e windows to reduce this problem.
Another safety consideration for low-e windows is its radio frequency attenuation. Simply stated, the metallic coatings utilized in the buildup of the glass panels interfere with radio waves. Most low e glass is composed of layers of silver. When a radio wave comes in contact with the silver in the glass, the metal will block some of the radio waves. The more layers of silver used in the window the more interference with radio waves the glass creates. While both the potential for fire ignition and loss of radio waves play against us as firefighters, the ability of the glass to reflect radiant heat can also help us. Low-e windows tend to hold up better under fire conditions.
As much as I would love to move on to another part of the building construction, we still need to address the shading devices for low-e windows. Permanent shading devices for windows are prescriptively required for windows “within 45 degrees of the nearest west, south, and east cardinal ordinate” (2012, ICC Green Construction Code). Windows that get a lot of sunlight are required to have shading provided. This shading can be accomplished in various ways such as other buildings, geological formations or the building architectural features. The theory is to let the light in, but not by an immense amount of direct sunlight. This translates into more obstacles for firefighters. Some of the most popular ways of getting the required shading is by placing louvers over the windows, designing the roof structure to provide a larger eaves, and overhangs. While the louvers create an additional element we must deal with during forcible entry, rescue, or ventilation, they are relatively easy to remove serving a lesser role than security devices.
While natural vegetation is not listed in the code as an acceptable permanent shading device, it is easy to see how some inspectors may allow natural vegetation to be approved. While our brothers and sisters in the world of wildland firefighting are trying to educate home owners in defensible space, many homeowners are considering moving more combustibles closer to their homes as a shading device. Lastly, overhangs can mean the eaves or a fabricated device. Keep in mind that an overhang that is added to the building may not be governed by local building codes. Consider all overhangs that are not part of the roof structure as unsecured. While you may need to perform fireground activities under these overhangs, do not work continuously under them, ladder against them, or stand on top of them.
Insulation Incidents
Unlike the interior environment, popular beliefs in construction 20 years ago in allowing a structure to breathe some to allow for some form of air circulation, current codes are quite contrary. With energy conservation being the ultimate goal in our green code and energy conservation code, buildings now must be sealed air tight. These are not prescriptive codes, but mandatory codes governing “Air leakage.” Traditionally, we could open up a wall and find a 1-inch hole drilled in the bottom of the wall to allow a single section of electrical wire that came up from the basement or lower floor. It was typical to see airspace around this wire and approved by code. Routinely inspectors in the field see wires and piping connecting rooms, floors, and with crawlspaces or basements. The intent of the code is to better insulate between conditioned and non-conditioned spaces within the home as well as the interior and exterior of the structure. This air-tight package helps us in many ways and can create problems in others. While compartmentation of the fire is a great asset, we may also not be aware the subtle signs of a potential backdraft or even of the presence of a fire from outside the building.
Because the demand for more insulation equals better efficiency, modern green construction contains high levels of insulation. Aside from our traditional fiberglass batt insulation or blown in Cellulose insulation, we are seeing a great increase in Spray Polyurethane Foam (SPF). This insulation is typically sprayed into the walls, flooring, and attic. SPF is a combustible product, however fortunately for us as fire suppression personnel, the foam does not readily sustain fire. In fact, the foam itself adds strength to the structure and due to reduced air leakage, modern construction aiding fire suppression efforts hinder or delay some fire extension. The application process of SPF is where we see one of our greatest concerns. Fires during application of SPF have been reported in the U.S. due to its heating properties, and some types of SPF are flammable while being sprayed. In July of 2015, NBC Connecticut reported that a fire in a multi-million dollar mansion in Middlebury CT, was a result of such a phenomenon. The fire originated in the attic space shortly after SPF was installed. The application of foam itself can cause a fire due to a chemical reaction of the products during foam mixing and curing.
While construction techniques are dramatically changing, the fire service industry seems to be lagging behind in proper education of these methods. Our homes are becoming more and more synthetic and the use of recycled and even reused materials are more and more prevalent. While many other areas of the current green codes were not addressed here, we need to take it upon ourselves to meet with our local code officials to see what codes have been adopted and any alternate building construction techniques are being utilized. We have seen everything from walls made of compressed straw to dry stack foam block walls. Methods of construction are changing at an alarming rate and we need to ensure the safety of our fire crews by researching what is being done in our local communities.
Related:
- International Green Construction Code, § 605-605.1.1.1 (2012). Print.
- "Middlebury Mansion Spontaneously Combusts." NBC Connecticut. 3 July 2015. Web. 25 May 2016.
Jeremy Loncar
Jeremy Loncar started his career in the fire service in 1995 with the City of West Wendover Fire Department where he is currently as a career fire captain. Loncar has been an Instructor and tester for the Nevada State Fire Marshal’s Office since 2005 and has taught as well as tested various departments throughout the state of Nevada and Utah in Hazardous Materials and Firefighting. he is also an ICC certified building inspector and plans examiner.
