The objective of this study was to conduct a demonstration and evaluation of roofing tile saws and the Hytile tile cutter at the Petersendean Roofing Systems training site. The study was conducted over two days. On the first day an experienced tile roofer demonstrated the Hytile tile cutter by cutting flat and curved roof tiles and showed that roof tiles could be cut quickly and cleanly. Short-term sample results showed personal exposures with the Hytile would be below the OSHA silica construction standard. A Bosch electric-powered saw with local exhaust ventilation was also tested and a short-term personal sample while using the Bosch electric saw was just below the OSHA construction standard PEL. On the second day apprentice and journeyman roofers demonstrated four saws and the Hytile tile cutter for interested parties including representatives from the Center to Protect Worker Rights (CPWR), the United Union of Roofers, Waterproofers and Allied Workers, Petersendean Roofing Systems (including representatives from Petersendean facilities in Newark and Southern California, Nevada, and Arizona), and the local roofers union. The roofing saws demonstrated included the Bosch handheld electric-powered saw, the Partner gasoline-powered saw, the Revelation saw, and the Bronco water backpack saw. Short-term personal respirable dust and crystalline silica samples were collected on the roofers demonstrating the Hytile tile cutter and one of the saws. The airborne sampling data indicated that exposures when using the Hytile cutter, if extrapolated for a full shift, would have been below the OSHA PEL for silica, while the silica exposures using the Partner saw would have been several times the OSHA PEL. Real-time sampling results showed that the respirable dust exposure using the Hytile cutter were approximately two orders of magnitude lower than when using either the Partner gasoline-powered saw or the Bosch saw. The Real-time sampling results are based on short sampling periods of about four to five minutes. Valuable input was provided by the observers at the demonstration. The use of the water backpack was found to be highly unfavorable because it was too heavy and water creates a slipping hazard on the roof. Material discoloration was also found to be an issue of the water suppression technique, since water provokes a staining on the concrete tiles. The Bosch 1364 was considered to be too heavy and was also considered cumbersome to use due to the addition of a 2 inch vacuum hose line from the roof to the vacuum cleaner. Most observers liked the Hytile and believed it could be used on the roof on valleys where smooth cuts are not required. Regular saws would still be needed for some cutting (e.g., for very smooth cuts). Virtually no visible dust was observed when cutting with the Hytile. One observer stated that the Hytile could be used for cutting about 40% of the roofing tiles while roofing a house - implying the remainder of the roof tiles would be cut using conventional methods. The Revelation saw brought to the demonstration was considered unacceptable by all the observers because the dust collector, to be effective, necessitating inactivating the blade guard. This demonstration study was very valuable in identifying directions for the NIOSH engineering control study for silica and respirable dust exposures in tile roofing construction. Specifically, the results showed: 1) cutters such as the Hytile appear to produce less dust and silica exposures than conventional saws

2) the quality of the cuts must be smooth in any visible part of the roof

3) the engineering control or work practice should not introduce an additional hazard such as falling or electrical hazard

and 4) add-on controls such as LEV must not significantly increase the weight of the tool or add safety and ergonomic hazards for the worker. As a result, NIOSH researchers need to continue to collaborate with roofing tile manufacturers, tool manufacturers, contractors, and employee representatives to identify and test potentially effective control methods.