### Safety Is Key
by Neeva-Gayle A. Candelori

Posted: June 8, 2010

When Applying SPF Roofing Systems

From rain and hail to sunli g ht and temperature extremes, a stron g roof must endure a variety of conditions and last a long time. For roofing systems, high-pressure, closed-cell spray polyurethane foam (SPF) has become a popular choice due to its du rability, and if installed properly, its ability to create a surface that resists permeation by water. SPF also is lightweight, easy to apply, and can create a uniform seal over the substrate regardless of different shapes and protrusions. Add to that its excellent performance as an insulation material and it’s easy to see why the long-term benefits of SPF are becoming more and more attractive to building owners.

The foam is created on the jobsit e out of two liquid components. The components react together to crea te foam. As you’ll learn in this article, because the liquid components contain certain kinds of chemicals, handling the components safely and wearing appropriate personal protective equipment ar e important. Always read all information contained in your supp lier’s Material Safety Data Sheet (MSDS), and follow the safe ha ndling guidelines provided.Learn About SPF

There are several “kinds” of spray foam that a contractor might encounter at a site. Although the term “spray polyurethane foam” can apply to several different kinds of products, in this article we address high-pressure, closed cell foam.

The foam itself is made by mixing batches of chemicals that are provided in separate drums. The chemicals must be kept separate until they are

mixed and the chemical reaction can be g in. The two separate drums or canisters have different
chemicals in them, and are referred to as the “A” side and “B” side. The A-side is typically a 50/50 mixture of methylene diphenyl diisocyanate (MDI) and polymeric methylene diphenyl diisocyanate (pMDI), or MDI-based diisocyanate. The B-side is a polyol resin blend — the principal ingredient being polyol — and smaller amounts of am ine and/or metal catalyst, blowin g agent, surfactant and flame retard ant. The drums may be color-coded
red or black for the A-side, and blue or another color for the B-side.

The degree of hazard (risk) presen ted from the chemical in the mix
varies. There is a difference, for example, in the amount of MDI available prior to mixin g the chemicals; after they are mixed and be g in reacting; and again after the reacti on has been fully completed and

the foam hardens. Extreme care must be taken when workin g with the SPF pre-mix chemicals and throughout every stage of the installation. Improper application by unprote cted workers could result in overexposure to the SPF chemicals, which can pose potential health

hazards.

Understand Potential Health Hazards

Potential health hazards of SPF ch emicals are discussed in the MSDS for the particular product, and workers should read and understand the MSDS before beginning work on a job. While we cannot review all the potential health effects that could result from spray foam chemicals here — and this specific information would be contained in the product MSDS — you should unde rstand that a worker could be exposed to SPF chemicals by breathing chemical mists or vapors, skin or eye contact, or ingestion. One of the key things to remember with spray foam chemicals is that the A-si de constituent, MDI, is considered a sensitizer. Inhalation exposure to MDI may lead to respiratory For roofing systems,high-pressure, closedcell spray polyurethane foam is lightweight, durable, easy to apply, and

can create a uniform

seal over the substrate regardless of different shapes. However, proper application and safety

measures are critical.sensitization. Respiratory sensitizatio n can lead to an asthmatic attack. Asthma attacks can be life-threatening events.

In addition, skin sensitization may occur as a result of skin contact
with MDI. In animals, skin contac t with MDI has led to respiratory

sensitization.

Wear Proper Personal Protective Equipment

To prevent inhalation of the SPF chemicals and contact with skin or eyes, personal protective equipment, or PPE, should be worn by all sprayers and helpers assisting them. Generally, for exterior applications like roofing, the following PPE is considered appropriate:

• A NIOSH-approved respirator appropriate for the anticipated workplace exposures. This may includean air purifying respirator (APR) or powered airpurifying respirator (PAPR) with organic vaporcartridges with particulate pre-filters or a suppliedair respirator (SAR).

• Disposable coveralls covering all exposed skin.

• Protective footwear, such as work boots.

• Nitrile, neoprene, butyl or PVC gloves.

Even when not spraying, PPE may be needed to prevent skin and eye contact during product handling in case splashes occur. Also note that the U.S. Occupational Safety & Heal th Administration (OSHA) requires employers to have a written Respir atory Protection Program (RPP) in place. OSHA makes available a Small Entity Compliance Guide that

contains criteria for the selection of a Respiratory Protection Program administrator and a sample progra m that meets OSHA requirements.

It is available at: www.osha.gov/Publications/SECG_RPS/secgrevcurrent.pdf

.

Plan Ahead For a Safe, High-Quality Installation

Site preparation: An important initial step before any installation is to analyze the site. Just as an import ant feature of any job is to keep The manufacturer’s Material Safety Data

Sheets should be consulted prior to applying coatings for

information on potential health

hazards and PPE

recommendations. OSHA requires that all MSDSs be readily

available to all

workers at the j obsite.workers protected, the j ob plan should also take into consideration the safety of bystanders. Carefully eval uate whether bystanders could be exposed to drifting spray foam chemic als and address this in your site plan. Don’t forget that spray foam is an exterior application and can drift into homes and buildings, po tentially impacting residents, so identify the location of air intake or exchange systems during the site analysis. It is a good practice to turn off the heating, ventilating and air conditioning system and all air handling units until the SPF has been sprayed and fully cured. In dense population areas, consider contacting nearby residents to assist them with similar measures, if

needed.

Developing an Overspray Mitigation Plan can help determine in

advance what actions will be taken in case of overspray. One feature of such a plan can be the advance id entification and training of a point person(s) on the crew on procedures to address spill clean-up and overspray issues. The higher the wi nd, the more spray can drift, so

ideal conditions for an outdoor SPF application have little to no wind. Depending on site conditions (e.g., population density, (subdivision or rural warehouse); nearby pedestrians; wind pattern and flow), it can be a good practice to postpone outd oor spraying in higher winds, such

as sustained or g usty winds exceedin g 15 miles per hour. Windscreens can also be an effective tool to help minimize overspray or spray drift.

Follow the SPF manufacturer’s inst ructions carefully, including instructions on application during specific conditions of temperature and/or humidity.

Discussion of the installation with the building owner: One of the most important elements of your preparatio n is to plan a discussion with the building owner or homeowner. Discuss any potential overspray or spray drift issues with the building ow ner or occupants as part of your site preparation. Implement steps as appropriate. Consider asking building occupants to move, addre ss building ventilation issues, and use tape or si g ns to mark both the work and potential spray drift area. Also consider pedestrian footpaths or bike paths, dog runs, or dog pens. After you have minimized potential for human exposures, consider whether additional steps could help protect property from overspray — such as relocating parked vehicles.

To protect the exterior of the build ing, a common practice is to cover any part of the building exterior that is not going to be sprayed (much like a painter places a tarp over a fl oor to keep it protected from paint spatters).During your discussions with the home owner, take the time to answer questions about how far away the bu ilding occupants should be from the installation — or whether they should vacate the building during the installation and for an appropri ate period after completion. Buildin g owners and occupants can also provide helpful assistance to you as you prepare the site, since they typi cally know the uses of their own property and air intake system we ll. SPF product suppliers can help provide you with specific guidance on questions regarding occupancy during the installation and reoccupancy times.

SPF application: Where feasible, plan the exterior application so that workers and helpers are upwind duri ng SPF application. Only workers wearing appropriate PPE should be allowed in the spray area.

Remember to consult the manufacture r’s Material Safety Data Sheet (MSDS) prior to applying coatings for information on potential health

hazards and PPE recommendations. Also , it is important to know that OSHA requires that all MSDSs be read ily available to all workers at the jobsite. Because these documents are important, a good workplace practice is to keep a clean copy of each MSDS in a clearly marked binder at the jobsite and to review the content and location of the MSDS binder with all workers before the job begins. MSDSs and other health and safety literature can be obtained by contacting your supplier.

As with any job, housekeeping and cleanup after the job is completed are important. Conduct jobsite qualit y controls throughout the project and dispose of waste materials in accordance with any applicable regulatory requirements. Empty drums can be given to a qualified reconditioner or reclaimer for recy cling. More information on drum reconditioning facilities can be found at www.reusablepackaging.org.

Spill response: It is advisable to have an emergency spill containment

kit available that contains absorben t materials such as clay, pads, or

socks to contain or mini mize the affected area. If a spill does occur, direct personnel away from the immediate area and send those workers designated for spill cleanup to address the spill after they put on the appropriate PPE. The spilled material can be absorbed with sand, earth or absorbent clays and pl aced in drums. If MDI has been spilled, a neutralization solution ca n be used according to the MSDS.

These drums should not be sealed fo r an appropriate period (e.g., at least 72 hours).

It is good practice to keep all chem ical containers sealed except whenthey are actually in use. Althou gh infrequent, sizable spills and

releases of A- and B-side chemicals can occur. If this happens, it is important to take immediate acti on to minimize environmental contamination. You may be required to report spills and releases of SPF and coating ingredients to local, state, and/or federal authorities.

First aid: Refer to the MSDS for inst ructions in the event of inhalation overexposure or skin or eye cont act with any chemicals over the course of your work. Any clothing contaminated with MDI should be removed and properly disposed of or decontaminated. Leather items

cannot be decontaminated and will have to be properly disposed of.

Help Spread the SPF Safety Message

SPF has a great future as a key co ntributor to comfortable, energy efficient homes. Everyone wants a professionally installed — safely installed — SPF system that performs well over time. Help us spread the safety message. And for additi onal helpful guidance, see the Center for the Polyurethanes Industry’s website on spray
foam, www.spraypolyurethane.com

.

Neeva-Gayle A. Candelori Neeva-Gayle A. Candelori is the Director of the Center for the Pol yurethanes Industry of the American Chemistry Council. She hol ds a B.A. degree in economics from the University of Maryland. Bringing over 15 year s of plastics industry experience to this role, she worked for leading chemical and pl astic industry trade a ssociations. Prior to j oining the American Chemistry Council, she held positions at The Society of the Plastics Industry and The American Plastics Council. Her prior roles involved managing industry issues for the vinyl, color and additives and the healthcare se ctors. She also serves as international advisory to the board of the Korean Polyurethane Society.