The rapid increase in ventilators used in hospitals due to the COVID-19 outbreak has increased the risk of fires due to oxygen enrichment in enclosed areas.
Ventilators are used to both provide mechanical breathing assistance and supplemental oxygen to patients who have difficulty breathing is a common occurrence in late-stage COVID-19 patients. The oxygen used with a ventilator may be supplied by stand-alone pressurized tanks or by connection to a hospital-wide bulk oxygen source. In either case, the oxygen ventilator, tubing, and connections to the ventilator have the potential to leak oxygen into the room resulting in oxygen enriched air.
Because oxygen is required for fire, increased oxygen levels in an enclosed room means fire can start more quickly, spread faster and burn hotter than in rooms filled with fresh air.
Oxygen Enrichment Dangers
Oxygen enriched air during ventilator use is the result of:
- Leaks from damaged hoses, pipes, connections and valves
- Valves left open either deliberately or unintentionally
- Poor ventilation where the oxygen is being used
Pressurized oxygen can raise the oxygen level in a room quickly. One liter of pressurized oxygen in a tank at 2,200 psi is the equivalent to 5 cubic feet of oxygen gas. If this were released into 12x12 foot room, it would immediately raise the oxygen level from 21% to 21.5%. During respiratory distress, oxygen flows from a patient's mask may reach 100 liters per minute or more.
Note that the same oxygen enrichment dangers apply to home supplemental oxygen tanks. Here are some additional tips for those who use oxygen at home:
- Don’t smoke near oxygen tanks. Most fires involving home-use oxygen are the result of smoking.
- Keep oxygen away from open flames. This includes gas stoves, grills, candles, fireplaces or any kind of fuel-burning space heaters.
- Avoid using electric razors, grinders, hair dryers or e-cigarettes. These are a source of sparks that can set off a fire in highly oxygenated air.
How Serious is the Risk?
While there are only a handful of cases each year of fires in hospitals intensified by oxygen enrichment, they do exist. According to the Federal Emergency Management Association (FEMA) between 2012 and 2014 there were 5,700 medical facility fires and 1,100 fires in hospitals in the US. While the majority of fires were related to cooking, between 1.6% of fires were the result of electrical equipment malfunctions.
For example, the Indian Journal of Anesthesia reported a near catastrophic ventilator fire leading to cardiac arrest in a patient during surgery. Sparks due to friction or an electrical short circuit within the oxygen ventilator may have acted as source of ignition leading to fire and explosion in the oxygen rich environment.
The ECRI Institute has published several cases over the years describing fires from defibrillation during oxygen administration when defibrillation produces an electric spark.
The increasing number of COVID-19 patients have resulted in some hospitals moving patients from private rooms to wards. The National Health System in the UK warned hospitals about “increased oxygen levels in the air” in wards repurposed to treat COVID-19 patients with ventilators. It went on to state that “the fire risk assessment for the area being converted should be reviewed in view of a higher life safety sleeping risk cohort and the additional issues of more oxygen being in use.”
In other words, even if all the oxygen ventilators are working properly, several of them in a single room could increase the oxygen level - and the potential file hazard.
Oxygen Enrichment Guidelines in the US
Oxygen storage systems in hospitals, institutions and industrial areas are covered under the United States Department of Labor Occupational Safety and Health Administration (OSHA) Guidelines 1910.104 Standard for Hazardous Materials – Oxygen. These general guidelines address the installation of bulk oxygen systems.
Oxygen Enrichment Guidelines Internationally
The European Industrial Gases Association (EIGA.eu) has published Fire Hazards of Oxygen and Oxygen-Enriched Atmospheres. This document is the most common international standard for bulk gas associations, covering the EU, Asia and Japan. It defines oxygen enriched atmospheres as exceeding 23.5% at sea level or whose partial pressure of oxygen exceeds 175 mmHg.
Regarding oxygen enrichment detection, the document states that:
“The method selected for oxygen detection shall offer a high degree of reliability of operation and be sufficiently sensitive to provide warning before a hazardous concentration of oxygen is reached. The usual method is to use an approved atmospheric monitoring instrument to confirm the effectiveness of the isolation and purging procedures before entry into the area and to periodically check during work to confirm that changes have not occurred.
If needed, oxygen measuring instruments should be used as warning devices only and should not be regarded as protection against the risks of oxygen enrichment. They should be seen as an addition to good practice of eliminating the causes of enrichment. Appropriate measuring instruments for the determination of oxygen content indicate an increase as well as a decrease of oxygen concentration in the ambient atmosphere.
Various measuring techniques and methods are used that give visible, audible, and/or tactile (vibration) warning, and they can be used for continuous or intermittent measurement. The manufacturer’s instructions for the use and maintenance of the measuring instruments shall be carefully followed.”
Oxygen Enrichment Safety: RACE
If an fire occurs in an oxygen-enriched environment, hospital personnel should follow the rescue, alert, contain and evacuate (RACE) procedure:
- Rescue patients in the immediate area of the fire. The person discovering the fire should perform the rescue if possible.
- Alert other personnel to the fire so that they can assist. The discoverer should also let others know of a fire by yelling "Fire in room 119!" while rescuing the occupants. Other personnel hearing the alert should relay the information to the facility switchboard or other alarm system.
- Contain the fire. Shut the door after rescuing the occupants to slow the spread of smoke and flame. Close fire doors. If oxygen and/or medical compressed air is in use in the room, shut off the zone valve controlling those gases to that room, and immediately assist all affected patients.
- Evacuate other patients and personnel in the areas around the fire. Facility personnel trained in fire emergency procedures should respond to the initial alarm to assist in evacuating patients to safe areas.
In addition to fire prevention, these additional tips are important in a potentially oxygen enriched atmosphere:
- Fire needs a spark/ignition, fuel and oxygen. Since anything non-metallic is a potential fuel and oxygen enrichment is potentially possible, pay attention to any source of sparks or ignition in the room like defibrillators, electrosurgical equipment, lasers, light sources or flames.
- Medical personnel using ventilators should be trained on proper operation of the device, especially in regards to connecting and disconnecting the machine from oxygen sources.
- Never force a tube connector into another connector. Make sure they are designed to mate properly for a proper seal.
- Know where the emergency oxygen shut-off valve is.
- Know where the nearest fire extinguisher, fire alarm, and fire escape is located as well as the proper procedure for contacting 911 in case of fire.
- Know how to cut off electrical power to the ventilator.
Oxygen Enrichment Safety Alarm
In addition to following the procedures to protect patients and staff from fire caused by a potentially oxygen enriched atmosphere, an oxygen enrichment safety alarm can be used. The safety alarm automatically sounds if the oxygen level in a room rises above 21% (normal) air. Our oxygen enrichment safety alarm includes a sensor unit to be mounted inside the room as well as a remote display that can be mounted outside the door to warn of high oxygen levels before entering the room.