NIOSH Urges Users to Test Scott II/IIA Pak Diaphragms
Users of Scott Air-Pak II/IIA and Pressur-Pak II/IIA self-contained breathing apparatus were advised to check for split or ruptured regulator diaphragms in a statement issued May 2 by the National Institute for Occupational Safety and Health (NIOSH).
“NIOSH tests investigating the effect of such defects showed reduced respiratory protection on demand-mode apparatus,” NIOSH Director Anthony Robbins, M.D., reported. “These same tests also showed no loss in protection, but a loss in service time when in the pressure-demand mode. The pressure-demand unit is not approved while in the demand mode; the demand mode is to be used for donning purposes only.”
Field test method
Robbins’ statement advised:
“Users should examine their Scott apparatus for possible damaged diaphragms in accordance with the manufacturer’s instructions. The user should check the diaphragm before each use by closing both the main line and bypass valves and blowing through the regulator port. It should be possible to maintain a slight positive pressure in the regulator. The user should check the regulator diaphragm after each use and during monthly inspections of the complete apparatus.
“It is not known if failure occurs during assembly, storage, or use of the regulator. Therefore, extreme caution must be employed when using the respirator.
“In checking the operation of the respirator,” the NIOSH statement continued, “users are cautioned not to block the flow of air from the regulator when the bypass valve is open because substantial obstruction may rupture or dislodge the diaphragm. If the user observes a loose or dislodged regulator cover, the cover must be removed and the diaphragm inspected before reassembly of the regulator.”
Scott statement
A statement from Scott Aviation, released by Lincoln C. Bailey, sales and marketing director, stated:
“As a result of field experience and tests to date, Scott Aviation feels that the only means of rupturing, slitting or tearing the diaphragm is through misuse of the apparatus either by blocking the regulator outlet with the bypass valve on and the system pressurized or by accidentally puncturing the diaphragm during field replacement.
“Our tests prove to our satisfaction that diaphragm failure will not occur during normal use of the apparatus,” Scott Aviation declared.
Bailey pointed out that thousands of units of the breathing apparatus models cited by NIOSH have been made by Scott during the last 15 years and they “have achieved an outstanding record for quality and reliability. We feel it is fair to assume that these products have saved more lives and prevented more injuries than any other respirator.”
Sales suspended
At the same time, Bailey said that Scott was acceding to a NIOSH request, “and it is a request,” he emphasized, to stop sales of the breathing apparatus models cited until the reason for diaphragm failure and corrective action to prevent it have been determined. Bailey also noted that the diaphragm field test suggested by NIOSH is the one recommended by Scott.
Robbins said that NIOSH started its diaphragm investigation “following the recent death of three fire fighters (in Lubbock, Texas) who were wearing this type of respirator, although it has not been established that the deaths were due to damaged regulator diaphragms.”
On this point, Scott stated, “Based on information we have received, we have no reason to believe that there is any connection between the use of Scott equipment and the unfortunate deaths of the firemen referenced in the NIOSH bulletin.”
The NIOSH statement reported that “a sampling of the apparatus in the field has shown at least 10 percent of the units examined have ruptured or punctured diaphragms.” According to Richard Ronk at the NIOSH breathing apparatus certification facility in Morgantown, W. Va., a number of fire departments throughout the country were asked to check the diaphragms of their Scott Air-Pak II/IIA and Pressur-Pak II/IIA units. Ronk said that the percentage of damaged diaphragms ranged from 2 to 30 percent in individual fire departments but that the average was 10 percent.
Questions may be addressed to Richard Ronk, NIOSH, 944 Chestnut Ridge Road, Morgantown, W. Va. 26505. His phone number is 304-5997337.
