- Some states are now requiring the installation of R-30 in walls and R-60 in ceilings, which requires almost 508 mm (20 in.) of fiberglass or mineral wool insulation.3 Some buildings cannot even support the depth of bays required.
- The National Flood Insurance Program (and FEMA) require only closed-cell SPF in any cavity which might be exposed to water.4
The good news is there are other energy-based codes addressing more sustainable and energy-friendly solutions such as closed-cell sprayfoam, and specifically, a new generation of single-step thermal barrier SPF technologies. One example is the International Energy Conservation Code (IECC), which provides for significantly less continuous insulation (c.i.) material when using an energy performance/savings measure for insulation and building envelope challenges.
‘Add-on’ products over plastics
SPF has historically met the code by being applied behind gypsum or covered with approved, add-on thermal barriers such as cellulosic and cementitious materials. SPF could also comply with code through “exception” methods using the lower-level ignition barrier approval (method two) or special approval testing (method three) via intumescent coatings as well.
When choosing one of these methods, commonly asked questions are:
- Which test(s) should be used?
- Which combination of coatings or cellulose or cementitious materials should be used?
- Over which foams?
- At which thickness?
- In which densities?
Addressing all the combinations of SPF/coating/cellulose/cementitious solutions and the appropriate paperwork needed for building officials is a separate topic in and of itself, requiring further discussion and explanation. However, understanding the add-on solutions is crucial and does need to be taught, as each skilled trade bears the responsibility for the safety of the construction process and the end-result.
One overriding thought to keep in mind is that manufacturers who supply plastics for the building envelope often claim their products are “fire-rated,” and although overly vague and misleading, they are partially correct. All plastics require a minimal level of fire rating to even be allowed for use in buildings. The problem is the robustness of the test procedures they reference.
Figure 6 shows a range of common fire tests that companies reference. A company could claim a “fire rating” from a simple Bunson burner test lasting only seconds, to full wall assemblies and ceilings that have achieved multi-hour ratings. Tests lasting mere seconds or claiming “self-extinguishing” properties with low-level heat or flame impingement provide less than acceptable protection for life safety.
Even when companies claim adequate fire approvals within the jurisdiction of 2603.4 (usually as a function of time), the test behind the measure can be confusing and/or inaccurately communicated, creating confusion and potential safety violations. A clear example of this confusion is the pass/fail time requirements (Figure 7) of exception tests (method three) versus the gypsum approval (method one) versus the equivalent thermal barriers (method four).
Prescriptive method one (gypsum) follows historical performance results and fire ratings are 15 minutes long, based on ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials. This is also sometimes called the compartmentalization of the fire test. It tracks and defines the time it takes for extreme heat to pass through a wall or ceiling to create a fire-risk situation in adjacent rooms to the space that have been compromised by fire.
Exception method three (special approval) defines a 15-minute period where flame spread and smoke generation from a known fire source in a 2.4 x 3.6 m (8 x 12 ft) room cannot exceed certain critical safety levels of flame and smoke. The flame and smoke growth maximums over the 15-minute duration estimate a safe amount of time to evacuate the space. Method three almost always defines systems’ (e.g. foam and coating together) capabilities which work in conjunction to achieve a exception level but “code-allowed” solution to life safety, but does not show compliance to temperature transmission risk in a structure. Although both test programs have 15-minute durations, they certify two very different life-safety criteria that are not interchangeable.
