The past several months have highlighted navigating the COVID-19 pandemic, the hyper-realization of the vital importance of the medical gas system, and the effects of increased demand on this critical infrastructure. As a result of pushing these systems to, or even beyond their designed limits, additional risk factors have emerged and should be addressed in the coming weeks and months.
While some areas and facilities have already experienced a peak in COVID cases and appear to be on a downward trend, other parts of the country are in the thick of this crisis. In addition, there is always the potential for a surge to reemerge in the future.
Regardless of an individual facility’s experience, now is the time to identify and evaluate potential risks and how to address them moving forward. While doing so, it is essential to remember that assessing these risks should not be based solely on the possibility of an asset failure, but on the overall impact that may occur when an asset does fail.
Below are some considerations to keep in mind during these unprecedented times.
Increased Demand on Oxygen Delivery Systems
Because the pandemic has resulted in an increased need for ventilators and the duration for which they are used, it’s clear that oxygen delivery systems have been affected. To address potential pressure drops within these systems as a result of the increased demand, some facilities have adjusted their final line regulators to increase the pressure of the entire system.
If this approach is taken, it is vital to remain within the NFPA 99 limits of 50-55 psi, as well as to adjust all area and master alarm high and low-pressure set points to stay ±20 psi of the operating pressure. It is also important to remember to document all changes, so any alarm adjustments can be made when returning the system to its normal operating pressure.
While most facilities have not experienced any issues with the actual supplied volume of liquid oxygen, the vaporizers have been identified as a potential weak link in a bulk cryogenic liquid supply system. In some instances, the increased flow of oxygen to the facility has been beyond the designed limits of the vaporizer. This results in excessive icing on the vaporizers and failures of controls downstream as a result of the liquid not converting to a gaseous state.
Most vaporizers rely on the movement of ambient air around the fans to allow the liquid oxygen to convert to gas. In times of increased demand, there are options available to combat excessive icing.
Potential short-term remedies include :
- Placement of fans around the vaporizer to increase airflow
- Ensuring proper timing of alternating type systems (if installed)
- Supplying additional capacity of oxygen through the emergency oxygen supply connection (EOSC)
- Back feeding individual zones
Installation of electric or steam vaporizer systems may also be worth assessing as a more permanent solution.
As required by NFPA 99, the suppliers of bulk cryogenic liquid systems shall provide an annual review of the source system to ensure it has sufficient capacity. Suppliers are also required to provide documentation of vaporizer sizing criteria to the facility upon request. It is recommended that all facilities work with their bulk suppliers during these annual reviews to identify any areas of potential risk.
Increased Demand on Medical Air Systems
Aside from the piped oxygen systems, increased demand has also been observed with medical air systems. Like the oxygen system, the increased flow of medical air can result in asset failures within the system. It is essential to provide frequent checks of these systems to ensure proper operation of medical air compressors, dryers, and filters.
Keep in mind that systems may require more frequent preventative maintenance as a result of increased usage. Areas of improvement may include increasing capacity through additional compressors or interconnecting with other medical air systems in the facility (if present).