An oxygen firebreak, also known as a fire stop valve or fire safety valve, is a thermal fuse designed to extinguish a fire in the delivery tube being used by a patient on oxygen therapy and stop the flow of oxygen if the tube is accidentally ignited. Oxygen firebreaks are fitted into the oxygen delivery tubing close to the patient, typically around the patient's sternum where the two nasal cannula tubes join and connect to the delivery tubing.
Video Oxygen firebreak
Home oxygen fires
Oxygen is not flammable, but when it is present in increased concentrations it will enable fires to start much more easily. Once a fire has started, if supplemental oxygen is present it will burn more fiercely, based on the principle of the fire triangle. Materials that do not burn in ambient air may burn when there is a greater concentration of oxygen present than there is in air.
Most home oxygen fires are caused by patients smoking whilst using medical oxygen. Despite the inherent dangers, researchers estimate that between 10 and 50 per cent of home oxygen patients continue to smoke. Other sources of naked flames, such as gas flames and birthday candles, can also pose a risk.
Once a fire has started in the patient's nasal cannula it will track back towards the oxygen source and if not stopped may lead to a 'whole house' fire. Whole house fires are directly correlated with single or even multiple deaths. According to the US National Fire Protection Association (NFPA), 25% of oxygen fires get beyond the immediate surrounding area to become 'whole house' fires.
While an oxygen firebreak / thermal fuse cannot stop the initial ignition, it can limit the potential for whole house fires, more serious injury and death. Firebreaks / thermal fuses can also buy more time for a patient and other individuals in the building to escape, and limit the material cost of fire damage.
Maps Oxygen firebreak
Oxygen fire statistics
In 2008 the NFPA published a report suggesting that there are 46 deaths each year in the US from 182 fires. The report also stated that US hospital emergency rooms deal with an average 1,190 cases of burns each year as a result of home oxygen fires. However, the NFPA describes these statistics as "likely underestimates".
Further analysis by Marty Ahrens on behalf of the NFPA in 2017 recorded a likely average annual death rate for home fires involving oxygen administration equipment of 70 people (or 3% or all home fire deaths), based upon figures between 2011 and 2015. The report also suggested that these fires or burns are becoming more common.
The United States Fire Administration (USFA) said in a 2015 report that "While no one factor is solely responsible for the increased fire risk to older adults receiving home health care, smoking in the presence of oxygen is recognized as one important problem."
A study of home oxygen therapy patients in the Veterans Health Administration between 2009 and 2015 examined 123 cases of reported adverse events related to flash burns. It found that 100 cases (81%) resulted in injury, and 23 (19%) resulted in death. Although 89% of veterans claimed to have quit smoking, 92% of burns occurred as a result of smoking.
Not all European countries monitor data on the number of fires that occur as a result of home oxygen. Despite a European Union Medical Device Directive requiring incidents to be reported to national vigilance authorities, there is often inadequate coordination to publish the information centrally. According to the German Federal Institute for Drugs and Medical Devices (Bundesinstitut fur Arzneimittel und Medizinprodukte, BfArM) it is likely that such incidents are grossly under-reported.
In England and Wales, central reporting of adverse incidents is a requirement of the NHS Service Specification for Home Oxygen. After firebreaks became mandatory in 2006, the average number of deaths by fire was 0.36 per thousand patients per year. In the US, where firebreaks were not required, almost twice as many patients (0.62 patients per thousand) died.
Home oxygen fire incidents
Recent and high-profile incidents involving deaths and injuries to patients, their relatives, and fellow residents, include:
San Remo, Italy. March 23, 2017
A woman died in a fire which started while she was smoking and simultaneously using her oxygen cylinder. Her husband also died trying to escape the blaze.
Pont-Sainte-Maxence, Oise, France. March 11, 2017
A 60-year-old wheelchair-bound patient, described as a 'big smoker', died when his liquid oxygen dewar exploded following a nighttime fire in his apartment. His wife also suffered injuries.
Pau, France. February 19, 2017
A patient died and an apartment was destroyed after medical oxygen cylinders exploded, leading to a fire. Fifteen other residents had to be relocated after the incident.
Winchester, Kentucky, US. March 11, 2016
Patient Jackie Hisle Jr. was sentenced to ten years' imprisonment on three counts of manslaughter after an incident in which his son, Donald Hisle, and two other residents were killed and six others were injured. Mr Hisle Jr. was smoking while using an oxygen concentrator, despite warnings.
Knox County, Tennessee, US. February, 2012
A jury awarded $2.5 million in damages against Apria Healthcare after the death of 72-year-old Jimmy Kelley from Knox County. The award was reduced to $1.275 million after the jury found Kelley to be partly responsible. Mr Kelley, a smoker, also used a space heater in a camper van where oxygen cylinders were stored.
Regulation
United States
Before placing a new concentrator on the market, all oxygen concentrator manufacturers need to make a 510(k) premarket submission to the US Food and Drug Administration (FDA).
If the manufacturer chose to apply ISO 80601-2-69:2014 to demonstrate the safety of the new device, the fire safety elements of the standard, including 'a means to extinguish a tubing fire and isolate the oxygen flow' are a requirement. Approval to market the product would then be based upon compliance to the standard.
In March, 2018, the US Veterans Health Administration issued a Patient Safety Alert mandating the use of thermal fuses in all its patients' home oxygen installations, unless there is a clinical reason for not doing so. The Patient Safety Alert applies to all patients, not just those deemed to be at 'high risk'. It requires two thermal fuses to be fitted per patient installation, and any unidirectional thermal fuses must be replaced with bidirectional versions at the next scheduled visit (unless the unidirectional thermal fuse is designed so it cannot be fitted in the wrong direction).
Europe
In the European Union the fitting of firebreaks is a legal requirement for all home oxygen installations.
All economic operators in the EU, including home oxygen service providers, must comply with the Medical Device Directive (93/42/EEC) or the Medical Device Regulation (2017/745).
The instructions for use for an oxygen concentrator placed on the EU single market must include an instruction to the effect that a firebreak shall be fitted close to the patient to stop the flow of oxygen in the event of a fire. By including this statement the oxygen concentrator manufacturer is complying with the harmonised EN ISO type standard for oxygen concentrators EN ISO 8359:2009+A1:2012, which provides the manufacturer with an immediate presumption of conformity to the Essential Requirements of the Medical Devices Directive and allows them to properly apply the CE mark. Since January 2015 all instructions for use provided with oxygen concentrators placed on the European market will include this statement.
The applied CE mark is reliant on the home oxygen service provider following this instruction and fitting a firebreak. If the firebreak is not fitted, then the Essential Requirements for performance and safety are not met and the CE mark is no longer valid. It also means that the home oxygen service provider's status, within the framework under which the single market for medical devices operates, changes from 'distributor' to 'manufacturer'. This has significant regulatory implications.
The EU Medical Devices Directive also requires that economic operators adopt solutions that 'reduce risk as far as possible' in line with the 'state of the art'. The fitting of firebreaks is therefore a requirement irrespective of the oxygen source, including oxygen concentrators, liquid oxygen dewars or gas cylinders.
United Kingdom
An additional legal requirement applies in the UK, where the fitting of firebreaks has been mandatory under the service specification of the home oxygen service since 2006.
Germany
In 2011, the German Federal Institute for Drugs and Medical Devices recommended 'corrective actions to prevent fires in oxygen concentrators'. It issued a notice stating that from July 1, 2012 all devices should be equipped with installations for stopping encroachment of the fire into the device, and interruption of the delivery of oxygen in the accessory as close to the patient as possible, in case of ignition. Manufacturers were also required to offer retrospective refitting for devices placed on the market before July 1, 2012.
World Health Organization guidance
The World Health Organization recommends 'firebreak connectors to stop the oxygen flow in the event of fire'.
Oxygen firebreak standards
Three main standards cover the use of oxygen firebreaks / thermal fuses:
- ISO 8359:1996/Amd.1:2012: Oxygen concentrators for medical use. Safety requirements
The safety requirements for oxygen concentrators are governed by the amended standard ISO 8359:1996+A1:2012. The US FDA recognized the standard from January 2014. In January 2015, it was superseded by ISO 80601-2-69:2014. Health Canada, which is responsible for national public health, still recognizes the standard.
- EN ISO 8359:2009+A1:2012: Oxygen concentrators for medical use. Safety requirements
All of the 28 CEN (European Committee for Standardization) national standardization bodies (NSBs) have published EN ISO 8359:2009+A1:2012 as national standards. In Europe EN ISO 8359:2009+A1:2012 has harmonized standard status, which triggers 'presumption of conformity'.
- ISO 80601-2-69:2014: Medical electrical equipment - Part 2-69: Particular requirements for basic safety and essential performance of oxygen concentrator equipment
Included in ISO 80601-2-69:2014 are specific requirements that serve to mitigate the risk of fire related to oxygen therapy. The requirements state that the following should be provided:
- A means to extinguish a tubing fire and isolate the oxygen flow in the accessories (nasal cannula and tubing or mask and tubing). The standard states that this should be fitted close to the patient.
- A means to prevent the fire spreading into the oxygen concentrator outlet. The standard states that the means can also stop the flow of oxygen although it is not required to do so. It also specifies that if a bubble humidifier is fitted to the concentrator, that the means must also protect the bubble humidifier.
References
Source of the article : Wikipedia
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