Asbestos Workplace Safety Guide

Roofing Safety Guide

Much roofing work with asbestos-containing materials is Class II work, requiring respirators or wet techniques. This includes removal of built-up roofing in which the roofing felts contain asbestos and removal of asbestos-containing shingles and asbestos-containing felt underlayments.

Other roofing materials, such as cements, coatings, mastics, and flashings may contain asbestos, and if these materials are not intact, their removal is a Class II operation. Removal of "intact" cements, coatings, mastics, and flashings, is not Class II work.

Asbestos-containing material (ACM) is considered non-intact if it has crumbled, been pulverized, or has otherwise deteriorated so that the asbestos fibers are no longer bound within a matrix. But breaking up intact ACM for removal does not necessarily make it non-intact for regulatory purposes. For example, in removing built-up roofing, workers might use a power roof cutter, or they might use chipping and scraping to remove material like cements and mastics. Roof mastics and cements are usually pried, chipped or scraped off; asphalt felt underlayments are sliced and rolled-up or sometimes scraped-off or chipped-off. The separation into smaller sections does not render the material non-intact material if it is otherwise intact.

Also, when otherwise intact roofing materials separates from the building, it does not necessarily become defined as non-intact. The condition of the smaller pieces must be examined to determine whether the material is non-intact.

On many roof removal jobs, the only asbestos is found in cements, mastics, coatings, and flashings. Because significant numbers of asbestos fibers are not released from such products when the material is intact, only minimal precautions are required. The material must be removed using manual methods and must not be sanded, abraded or ground. Material that has been removed from a roof must not be dropped or thrown to the ground and must be removed from the roof by the end of the work shift. Prior to the start of the job, the material must be examined by a competent person to determine whether it is intact and is likely to remain intact throughout the job. The employees must be trained in the hazards of asbestos exposure and the proper work practices and prohibitions applicable to such work.

Installing new asbestos-containing materials

Within the United States, the only ACM currently being installed on roofs are certain coatings, cements, and mastics. When materials labeled as containing asbestos are installed on non-residential roofs, the contractor must notify the building owner of the presence and location of the asbestos-containing material.

Removing material

There are plenty of manual methods for removal of asbestos that are safe when used in the right manner and with the right precautions. These methods include the use of spud, spade, flat-blade or slicing tools, such as axes, mattocks, pry bars, spud bars, crow bars, shovels, flat-blade knives, and utility knives, to slice, cut, strip-off, or pry-up the material.

OSHA requires nails require are to be cut they must be cut with a flat, sharp instrument. If the nails are not to be cut, the nails can be pulled out.

Air monitoring

In their tests of actual construction sites, OSHA found that when the right work practices are followed, asbestos in the workplace air is well below the permissible exposure limit. Therefore, the agency does not require monitoring the air for asbestos if the on-site competent person determines that the asbestos-containing material is intact and that employees have been properly trained.

If the material is not intact, it must either be lowered to the ground immediately or must be bagged, wrapped, or kept wet while it remains on the roof. Whether or not the material is intact, it must be lowered from the roof no later than the end of the work shift.

HEPA-vacuuming

The ordinary accumulation of environmental dust and debris on a roof will not require HEPA-vacuuming. Only if there is an indication that non-intact ACM is the source of dust or debris must that dust or debris be HEPA-vacuumed. When the roof has an aggregate surface, the dust must be collected by a HEPA vacuum or HEPA dust collector.

Sweeping

It is often appropriate to remove accumulated dust and debris from a roof to reduce the total atmospheric contamination produced by the removal job. Power brooms are sometimes used for this purpose. Dry cleanup of dust and debris is permitted unless the dust and debris is associated with non-intact ACM.

When a power roof cutter is used to remove a built-up roof the blade of the cutter must be continuously misted during use unless a competent person determines that misting substantially decreases worker safety. If the roofing material is non-intact, before removal work begins, additional wetting and/or other precautions, such as use of hand methods and respirators, may be needed.

Sloped roofs

Although the respirators are required for Class II asbestos work when wet methods are not used, there is an exception when shingles are removed from sloped roofs. Because respirator use reduces visibility and mobility and would therefore be hazardous on sloped roofs, respirators are not required if a negative exposure assessment has been made and the ACM is removed in an intact state.

Wetting shingles will often make them slippery and lead to slipping and falling hazards that can be particularly dangerous on sloped roofs. Wetting of intact shingles is therefore not required. Wetting of non-intact shingles is required where feasible but the shingles need not be wetted when the competent person determines that wetting would create slipping and falling hazards.

Respirators

In roofing work, respirators are required

when wet methods are not used during removal of non-intact material
when the material does not remain substantially intact during removal
when the employer is unable to make a negative exposure assessment
when asbestos exposures exceed the permissible exposure limit.

Small roofing jobs

When a contractor repairs or removes less than 25 square feet of a roof in a single day, HEPA vacuuming and wet methods need not be used. This exception only applies, however, when manual methods are used to remove the material and no visible dust is created.

Building air intakes

Air intakes on the roof within the regulated area must be isolated or shut down.

Isolation techniques include use of

a buffer zone
HEPA filters over the air intakes
horizontal or vertical extensions that relocate the opening of the air intake outside or above the regulated area or away from or above a nearby upwind source of asbestos fiber emissions
covering the intake with plastic sheeting or other barrier.

The competent person must use good judgment to choose an appropriate isolation method based on the circumstances of the particular job.

Working with Asbestos Material

The Occupational Safety and Health Administration imposes strict guidelines for working around asbestos-containing materials. Controlling the exposure to asbestos can be done by three methods. Engineering controls include such things as isolating the source and keeping the area well ventilated. Administrative actions include closely tracking and limiting the length of time workers are exposed and providing showers for them when their shift is done. Showering is very important for removing all traces of asbestos fibers that may remain on the body after a work shift. Personal protective equipment is absolutely essential for minimizing asbestos exposure. Providing proper respiratory protection and clothing, along with training on how to use them, can go a long way towards minimizing exposure. Employers are required to follow these guidelines, and workers each need to understand the risks and take personal responsibility for protecting themselves by following them as well.