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Types of Spray Polyurethane Foam Products

Spray polyurethane foam (SPF) is a highly-effective and widely used insulation and air sealant material. However, exposures to its key ingredient, isocyanates, and other SPF chemicals in vapors, aerosols, and dust during and after installation can cause asthma, sensitization, lung damage, other respiratory and breathing problems, and skin and eye irritation.

To create the final SPF insulation or sealant product, a chemical reaction of two component parts has to occur. Chemicals in SPF products leave the gun, nozzle, or straw and form a foam as the chemicals react. Safe work practices should be in place to avoid exposure at every stage of SPF installation.

The chemical components, particularly isocyanates, and related hazards are similar for the various types of SPF products on the market. The polyol blend (side B) of SPF products contains a variety of proprietary chemicals that provide specific performance functions i.e, catalyst, flame retardant etc.

However, the amount of product used, the delivery mechanism, and overall application process differs for each type of SPF product; therefore, the potential for exposure may vary, though there is potential for eye, skin, and inhalation exposure to hazardous chemicals with all types of SPF products. Remember to use the appropriate protection and best practices suited for each type of SPF product.

Types of Spray Polyurethane Foam Products
There are three main types of SPF products, each of which have different application uses, but all the SPF products require the use of protective equipment in order to prevent exposure to isocyanates and other SPF chemicals.  See below for more information on the differences and similarities of the SPF products.

For more information on the distinctions between the various spray polyurethane foam products and guidelines that should be followed during application whether you’re a homeowner hiring someone to install spray polyurethane foam (SPF) for you, a do-it-yourselfer, an SPF contractor, builder or weatherization professional, visit the American Chemistry Council’s Center for Polyurethanes Industry Spray Polyurethane Foam Health and Safety website. Exit EPA Disclaimer

Information on the Various Types of Spray Polyurethane Foam Products
SPF Types
Two-component
High-Pressure



Open-Cell (low density, half lb.)
Closed-Cell (medium density, 2 lb.)
Closed-Cell (high density, 3 lb.)
Two-component
Low-Pressure


One Component Foam
(OCF)



Uses
  • Larger insulation applications;
  • Air sealant in hybrid insulation installation with fiberglass or other insulation material
  • Roofing applications (Closed-Cell, high density,
    3 lb.)
  • Air sealant;
  • Adhesive;
  • Smaller insulation applications;
  • Weatherization activities
Sealant for filling cracks, holes, gaps, and crevices:
  • Around windows and doors;
  • For sealing up small gaps (0.5" - 3") in a building to create an energy efficient building envelope
This product is inappropriate for "creative" uses such as science or art projects and should not be used around children.
Applicator Professional Installer
  • Professional Installer;
  • Weatherization worker;
  • Available for do-it-yourself applicators, but the same precautions should be taken as with professional-use. DIY applicators are often unaware of inhalation and dermal hazards and may not have adequate knowledge, training and experience to wear adequate personal protective equipment.
  • Professional Installer;
  • Weatherization worker;
  • Available for do-it-yourself applicators but note that the same precautions should be taken as with professional-use
Container size 55 gallon drum containers Typically three to five gallons per container from the system house, but can be purchased in larger containers over the internet or in some retail markets Available in retail and hardware stores nationwide in a variety of sizes ranging from 12 oz. to 24 oz. cans
Engineering Controls Ventilation and containment practices should be considered to control chemical exposures. Work in "permit-required" confined spaces as defined by OSHA, which may include work in attics and crawl spaces, requires entry procedures, including an entry permit, and training for the workers.

OSHA requires a hierarchy of controls, under which employers must first implement engineering controls where feasible. Consult the safety data sheet for additional guidance on the use of Personal Protective Equipment (PPE) and Respiratory Protection when the use of engineering controls are not feasible or adequate to control exposures. See below for personal protection recommendations for each type of SPF product. 
Personal Protection Personal Protective Equipment:
  • Supplied Air Respirator;
    Loose fitting respirators are available and do not require fit testing. Respirators with a tight face seal require a fit test. For more information, see OSHA's Respiratory Protection Standard (29 CFR 1910.134).
  • Eye protection
  • Chemical resistant clothing;
  • Chemical resistant (e.g., nitrile) gloves so that no skin is exposed
Receive Medical Surveillance to ensure applicator is healthy enough to wear respirator. Ensure all equipment is intact upon use and ensure proper equipment maintenance. Vacate all unprotected workers and building occupants.
Personal Protective Equipment:
  • Air Purifying Respirator; Replace cartridges on appropriate change-out schedule. Respirators with a tight face seal require a fit test. For more information, see OSHA's Respiratory Protection Standard (29 CFR 1910.134).
  • Eye protection
  • Chemical resistant clothing;
  • Chemical resistant (e.g., nitrile) gloves so that no skin is exposed
Receive Medical Surveillance to ensure applicator is healthy enough to wear respirator. Ensure all equipment is intact upon use and ensure proper equipment maintenance. Vacate all unprotected workers and building occupants.

Read more information about personal protection when using two-component low pressure kits. exit EPA
Personal Protective Equipment:
  • Eye protection
  • Chemical resistant clothing;
  • Chemical resistant (e.g., nitrile) gloves so that no skin is exposed
Avoid breathing vapors and provide adequate ventilation. Consult safety data sheets for additional respiratory guidance when needed. Ensure all equipment is intact upon use and ensure proper equipment maintenance. Vacate all unprotected workers and building occupants.
Chemical Composition SPF products contain approximately 50 percent Side A and 50 percent Side B. This chemical reaction generates heat. Side A contains very reactive chemicals known as isocyanates. Side B contains a polyol, which reacts with isocyanates to make polyurethane, and a mixture of other chemicals, including catalysts (which help the reaction to occur), flame retardants, blowing agents and surfactants.
Variations in Chemical Composition Open-Cell Blowing Agents:
Carbon Dioxide or Water
Closed-Cell Blowing Agents:
HFC-245fa
 
Application Process Sides A and B are pumped through heated hoses from supply tanks into a nozzle where the two components react and are spray applied at elevated temperatures (>150°F) and pressure (1200 psi). “Open” cell foam expands more vigorously than “closed” cell foam and should be applied in layers. See photographs below illustrating expansion differences between open-cell and closed-cell SPF. Foam can expand up to 120 times its original volume. After the foam is applied, has expanded, and has cured, it may be trimmed or cut, as needed; this might especially be true for the use of “open” cell foam that may expand beyond the wall. Sides A and B combined at application site and sprayed on as a stream or bead. After the foam is applied, has expanded, and has cured, it may then be trimmed or cut, if needed. OCF components are pre-reacted and undergo further reaction with ambient moisture at the time of application (moisture cured). Applied as stream or bead. May be trimmed or sanded.
Chemical Exposure Potential May be exposed to chemicals:
  • During application
  • After application
  • During heat-generating processes such as drilling, welding, or sanding
  • During fires
Through:
  • Aerosols
  • Vapors
  • Dust that may contain unreacted chemicals
May be exposed to chemicals:
  • During application
  • After application
  • During heat-generating processes such as drilling, welding, or sanding
  • During fires
Through:
  • Aerosols
  • Vapors
  • Dust that may contain unreacted chemicals
May be exposed to chemicals:
  • During application
  • After application
  • During heat-generating processes such as drilling, welding, or sanding
  • During fires
Through:
  • Aerosols
  • Vapors
  • Dust that may contain unreacted chemicals
Hazards
  • Asthma
  • Sensitization
  • Lung damage
  • Other respiratory and breathing problems
  • Skin and eye irritation
  • Asthma
  • Sensitization
  • Lung damage
  • Other respiratory and breathing problems
  • Skin and eye irritation
  • Asthma
  • Sensitization
  • Lung damage
  • Other respiratory and breathing problems
  • Skin and eye irritation
Re-Entry Some manufacturers estimate that it can take 23 to 72 hours for the foam to fully cure after this type of application, but curing rates can vary. Some manufacturers estimate that it can take 23 to 72 hours for the foam to fully cure after this type of application, but curing rates can vary. Some manufacturers estimate that it can take 8 to 24 hours for one component foam to cure, but curing rates can vary.

Photo showing open-cell foam expanding beyond the 2x4 of the wall.   Photo showing closed-cell foam expanding up to the 2x4 of the wall.
Open-Cell SPF Two-component “Professional” High-Pressure System:
- Low Density
- Expands aggressively
- Dries soft
- Lower R-value (~ 3.5 per inch)
*Photo Courtesy CertainTeed
  Closed-Cell SPF Two-component “Professional” High Pressure System:
- High Density
- Expands less aggressively
- Dries rigid
- Higher R-value (~ 6.5 per inch)
*Photo Courtesy CertainTeed

Information on Other Insulation Products

For information on other Insulation Products, visit the Department of Energy's Energy Savers Types of Insulation, the Occupational Safety and Health Green Jobs website or the ENERGY STAR® Air Seal and Insulate website. Read more information on the ENERGY STAR® program as it relates to SPF.


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Free Online Training Available!

Applicators and helpers:Receive free basic online training Exit EPA Disclaimer available on the American Chemistry Council’s Center for Polyurethanes Industry SPF Health and Safety website for preliminary information. Applicators should also receive classroom and hands-on instruction on the safe use of SPF offered by the Spray Polyurethane Foam Alliance Accreditation Program Exit EPA Disclaimer and SPF system houses.


Health Risks and Alerts on Isocyanates

Isocyanates, are potent eye, skin, and respiratory irritants, reported to be the leading attributable chemical cause of work-related asthma.

Isocyanates are powerful sensitizers that can trigger a severe and potentially fatal asthma attack in sensitized persons if exposed to even very low levels of isocyanates.

The National Institute for Occupational Safety and Health (NIOSH) issued two Alerts to prevent asthma and death from exposures to isocyanates:

Exposures to isocyanates should be reduced to the lowest possible level.

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