General Technical Information

DO SIPs CONTAIN FORMALDEHYDE? (technically yes, realistically no)

The answer to this question is technically yes, realistically no. This is the case because the amount of formaldehyde emitted by the oriented strand board (OSB) used in SIPs is less than 0.1 PPM (parts per million). This is well below levels established as acceptable by the U. S. Department of Housing and Urban Development, (HUD). In fact, the HUD Standard now in effect exempts OSB that is produced with these phenolic type adhesives. Large chamber testing demonstrated that emissions of formaldehyde from OSB is less than would be encountered in the normal atmospheric levels of an urban environment. Testing done by APA - The Engineered Wood Association, has been extensive and conclusive. With their permission, a report that provides more detail on this subject has been reprinted and is available from the APA or SIPA offices. The rigid foam cores and the structural water base adhesives used in the panel manufacturing process have no formaldehyde content and are inert plastics prior to leaving SIP manufacturing facilities.

HOW DO SIPs REACT IN A FIRE?

Manufacturers across North America have proven the fire performance of SIP systems through some of the most extensive fire assembly testing in the construction Industry. The results of this destructive testing allow documentation of SIP performance under rigorous test standards. National standards like ASTM - E119, ASTM - E84 and UBC 17 - 5 have been met by protecting SIPs in a similar fashion as other wood based structures. ’One Hour’ fire resistive assemblies are achieved by combinations of underlying structure and protection of that structure by Gypsum Wall Board.

Residential structures are typically required to meet a fifteen minute standard and meet that standard by applying ½" common gypsum over Structural Insulated Panels.

Light commercial and multi-family structures can be required to meet the more restrictive one-hour fire resistive standards. Some of these prescriptive assemblies are listed in the UL® Fire Resistive Assembly Manual, but can be summarized as follows;

1.) Two layers of 5/8" ’type X’ gypsum, attached per the Manufacturers code report, on structural insulated panels with various connections.

2.) One Layer of 5/8" ’type C’ gypsum, attached per the Manufacturers code report, on structural insulated panels joined with dimensional lumber or solid engineered wood products at 48" on center or closer.

As with any fire resistive issue, the local jurisdiction requirements will vary by region, building classification and structure occupancy. You should contact your local building and fire departments to determine those local requirements and involve the design professional to ensure compliance with local and national codes.

WHY DO SIPs BUILDINGS REQUIRE MECHANICAL VENTILATION?

As we have insulated and sealed homes to achieve greater levels of comfort and energy independence, Structural Insulated Panels have proven themselves to be the most cost effective and stable method of construction. Although this simplified process of super-insulation has shown positive impacts on the quality, comfort and energy savings of structures, it also created the need for controlled ventilation. Many of today’s indoor airborne pollutants can be effectively controlled, actually increasing the comfort and livability of a structure.

Mechanical ventilation has been proven effective in mitigating fumes from combustion appliances, radon, formaldehyde and even pollutants such as excess humidity and tobacco smoke. Established levels of humidity levels are governed by region, but a rough rule of thumb is 50% relative humidity on the interior of a building will be low enough to inhibit mold or mildew based pollutants and high enough to inhibit low humidity pollutants like dust mites.

In order to remove the contaminated air, an exhaust is essential. Typically, that exhausted air is the replaced with fresh air from outside the structure. Several methods of accomplishing this are available. They are listed as follows:

• Air to air heat exchangers - These small units generally draw air from source areas like kitchens and bathrooms where excess humidity is created. Moisture laden warm air is carried through ducts to the unit where it transfers the heat through a core, similar in function to the radiator of a car, while carrying the moisture out of the structure. Thus, the exhaust air tempers or pre-heats the cold unconditioned but fresh air that is coming in from outside. These units are also known as HRV’s or Heat Recovery Ventilators.
   
• Exhaust only systems - These come in many shapes and sizes from simple one room units to multiple duct whole house exhausts. These units typically exhaust the stale air and rely upon natural infiltration to replace the exhausted air. They can create a negative pressure on the structure.
   
• Ventilating windows - These windows use a small grille to both exhaust and replace air in a house. They are manually operated and can be used in selected or every window in a home.
   
• Air Cleaners - These units run the gamut from inexpensive tabletop versions to very sophisticated whole house systems. They are used to remove particulate pollutants but generally are not designed for the removal of gaseous pollutants. Typically these are not recommended for either humidity or radon control.

Whatever your choice in mechanical ventilation, your design professional should be deeply involved in any indoor air quality maintenance design. Several sources are available for in depth objective information on the subject of air quality. Some are listed below:

• National Center for Appropriate Technology
  P.O. Box 2525
  Butte, MT 59702-2525
  (800) 428-2525
   
• Energy Efficiency and Renewable Energy Clearinghouse
  P. O. Box 3048
  Merrifield, VA 22116
  (800) DOE-EREC