امنیت کاری در نصب شینگل
The introduction and rapid acceptance of single-ply membranes into the U.S. roofing market in the 1970s was likely the most significant roofing industry change in twentieth century. Another notable development in the 1970s was the widespread acceptance of plastic foam roof insulations, although this pales in comparison with the development of single-ply membranes. It is doubtful that another issue will be as revolutionary as the introduction of the single-plies. Since the single-ply revolution, changes in the roofing industry have been primarily driven by environmental and worker health issues and the pursuit of methods to reduce the amount of labor needed to install roof systems.
WORKER HEALTH REGULATIONS
The most notable impact of worker health regulations on the roofing industry pertained to asbestos. Prior to 1990, asbestos fibers were used in a variety of products, including asbestos-reinforced base flashings for built-up roofs, asbestos-fibrated roof coatings and asphalt roof cements and cement-asbestos shingles. The asbestos-containing roofing materials generally offered very good performance, but due to health concerns of workers exposed to asbestos fibers during product manufacturing, product installation and roof system demolition, asbestos-containing fibers have for the most-part been phased out. In many instances, the reinforcing fibers and products that were initially introduced to replace asbestos offered very poor performance.
In the late 1990s, health concerns related to development of mold in buildings were raised. Though the water necessary to initiate mold growth can come from a variety of sources such as leaking pipes and windows, leakage from roofs is a common source of water. The mold issue has taught building owners, designers, contractors, and roofing materials manufacturers, the importance of quickly responding to leakage reports. With a quick response, the source of the leakage can be identified and corrected and steps taken to dry the building before significant mold bloom occurs.
The most notable impact of environmental regulations on the roofing industry pertained to phasing out chlorofluorocarbon (CFC) blowing agents in the 1990s. CFC was used to manufacturer extruded expanded polystyrene, polyunsaturate, and spray foam insulation. CFC was phased out because of its role in global depletion of atmospheric ozone. As an interim measure, hydro chlorofluorocarbon (HCFC) blowing agents were used in the 1990s and early into the 2000s. HCFC had a much lower ozone depletion potential than CFC. It was not until introduction of the third generation blowing agent, hydro-fluorocarbon (HFC) that a blowing agent with a zero ozone depletion rating was available. The development of the second and third generation blowing agents was technically challenging. Though the phase-ins of the new agents were generally successful, product performance problems were experienced. There are concerns about hot kettles, working with hot fluids, falls from roofs during construction, coal tar and carcinogens, and working with open flames.