A Medical Device Daily

The FDA and the National Institute for Occupational Safety and Health (NIOSH; Washington) yesterday jointly issued an alert concerning the danger of fires “at the interface of oxygen regulators and cylinder valves because of incorrect use of CGA 870 seals.“ The agencies said they had received 12 reports in which regulators used with oxygen cylinders have burned or exploded, in some cases causing injuries.

The agency said that some of the incidents occurred during emergency medical use or during routine equipment checks.

The alert included information concerning precautions to take to avoid such fires.

“FDA and NIOSH believe that improper use of gaskets/washers in these regulators was a major factor in both the ignition and severity of the fires, although there are likely other contributing factors,“ it said.

Two types of washers, referred to as CGA 870 seals, are commonly used to create the seal at the cylinder valve/regulator interface: The type required by many regulator manufacturers is a metal-bound elastomeric sealing washer designed for multiple use applications; the other common type, often supplied free-of-charge with refilled oxygen cylinders, is a plastic (usually Nylon) crush gasketsuitable for single use applications.

“The nylon crush gaskets require higher torque than the elastomeric sealing washers in order to seal the cylinder valve/regulator interface, and if they are used again, they require more torque with each successive use,“ according to the alert. “The cylinder valve/regulator connection is designed to be hand-tightened. If the crush gaskets are re-used, the need for increased torque may require using a wrench or other hand tool, which can deform the crush gasket and damage the cylinder valve and regulator.“

This can result in leakage of oxygen past the cylinder valve seat and across the nylon crush gasket. According to a forensic analysis supported by FDA and NIOSH, “flow friction“ caused by this leakage of compressed oxygen across the surface of the crush gasket may produce enough thermal energy to spontaneously ignite the nylon gasket material.

FDA and NIOSH recommend that plastic crush gaskets never be reused, as they may require additional torque to obtain the necessary seal with each subsequent use. This can deform the gasket, increasing the likelihood that oxygen will leak around the seal and ignite.

It also outlined a variety of general precautions to avoid the explosions and fires:

  • opening the valve just enough to allow gas to escape for a very short time before attaching regulators in order to expel foreign matter from the outlet port of the valve.
  • always following the regulator manufacturer's instructions for attaching the regulator to an oxygen cylinder.
  • always using the sealing gasket specified by the regulator manufacturer.
  • always inspecting the regulator and CGA 870 seal before attaching it to the valve to insure that the regulator and seal are in good condition and the regulator is equipped with only one integral metal and rubber seal that is in good condition.
  • tightening the T-handle firmly by hand, not using wrenches or other hand tools that may over-torque the handle.
  • opening the post valve slowly, while maintaining a grip on the valve wrench so that it can be closed quickly if gas escapes at the juncture of the regulator and valve.

Healthcare Acquisition now HAPC

Healthcare Acquisition Partners (New York) said that the company has changed its name to HAPC and, effective at the opening of the market as of April 25, the company's ticker symbol on the OTCBB was HAPNU.

The company is a “blank check“ company recently formed for the purpose of acquiring, through a merger, capital stock exchange, asset acquisition or other similar business combination, one or more operating businesses in the healthcare industry.