Cause of Device-Related Incident
Device factors; External factors; User errors

Clinical Specialty or Hospital Department
Anesthesia; CCU / ICU / NICU; Clinical/Biomedical Engineering; CSR / Materials Management; Emergency Medicine; Nursing; OR / Surgery; Pulmonary / Respiratory Therapy

Device Factors
Design / labeling error

Document Type
Hazard Reports

External Factors
Medical gas and vacuum supplies

Mechanism of Injury or Death
Fire

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Device misassembly

UMDNS
Regulators, High-Pressure Gas [13-323]; Medical Gas Cylinders [16-501]

Oxygen Regulator Fire Caused by Use of  Two Yoke Washers



Hazard [Health Devices Nov 1990;19(11):426-7]

Problem

An ECRI investigation of a fire that occurred between an oxygen regulator and an E-cylinder valve revealed that the fire resulted from the use of two washers between the regulator body and the E-cylinder yoke. In this incident, a specific model oxygen regulator, which had a durable washer, had been placed on a new E-cylinder without first removing the cylinder's disposable washer. The use of two washers allowed an oxygen leak on the high-pressure side of the regulator, which, in the presence of minor hydrocarbon contamination, resulted in a flash fire between the regulator and the cylinder valve.

Discussion

Most new oxygen regulators are supplied with a plastic or nylon yoke washer that may develop leaks with repeated use. Hospitals tend to remove these washers and use the disposable yoke washer that is commonly supplied with a new oxygen cylinder. However, this model regulator is supplied with a replaceable, durable, partially metallic yoke washer that is less susceptible to developing leaks. Users familiar with nylon washers may not be aware that this regulator has a more durable washer, especially since this regulator is most commonly used in the prehospital environment. In addition, the manufacturer's operating instructions and labeling do not inform users of the washer's new design and use in its regulator. At least one other regulator manufacturer, of those known to ECRI, also markets regulators with durable yoke washers.

Action

With the new design, it is essential that any washer present on an oxygen cylinder yoke be removed before installing the oxygen regulator. Only one washer of any type should be used at any time. We encourage all manufacturers of oxygen cylinder regulators equipped with durable yoke washers to label their regulators with instructions to remove the yoke washer on the cylinder before installing the regulator. In the interim, we urge users to follow the recommendations below.

Recommendations

  1. Determine whether your oxygen regulators are equipped with a durable yoke washer. If so, affix a label or tag stating: This regulator is equipped with a durable yoke washer. Remove any washers from the oxygen tank cylinder before installing the regulator.
  2. Ensure that all respiratory therapy, nursing (including nurses aides), emergency medicine, and anesthesia personnel are made aware of this report.
  3. If you are uncertain whether your oxygen regulators are equipped with a durable washer, contact the regulator supplier.

UMDNS Terms

  • Regulators, High-Pressure Gas [13-323]
  • Medical Gas Cylinders [16-501]

Cause of Device-Related Incident

Device factor: Design/labeling error

User error: Device misassembly

External factor: Medical gas and vacuum supplies

Mechanism of Injury or Death

Fire


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