Medical Gas Zone Valve Replacement
Recently, a very unique, challenging and costly medical gas maintenance project was undertaken and completed at Cleveland Clinic. Because many medical gas systems installed in our older buildings are dated, some of the components did not meet current NFPA 99, Standard for Health Care Facilities, requirements.
In an effort to support our 1,300 patients by continually improving our medical gas pipeline systems to the point that they become as reliable and safe as possible, we accepted this challenge voluntarily and earmarked the funds.
This article explains a unique challenge encountered regarding the replacement of about 60 out-of-date zone valve box (either single or multi-valve) assemblies campus wide. Most lacked pressure indicators on the patient side, which are required for new installations. Others had slightly leaking packings or no longer provided 100% shutoff and were not repairable
Because NFPA 99 does not require the replacement of equipment if it “…does not constitute a distinct hazard to life” (220.127.116.11), it must be emphasized that this project was initiated voluntarily. However, zone valves that lack pressure indicators on the patient side could present a negative patient safety possibility.
To explain, dated zone valves that lack pressure indicators present a possible danger to patients because while observing a zone valve with no pressure indicator, the facility cannot tell if the zone is truly pressurized or what the actual pressure in the zone is. Observing the handle in the “on” position does not positively indicate that the zone is pressurized because an upstream service valve may have been turned off, and system pressure reduced to atmospheric, without the knowledge of the facility.
This article addresses the replacement of zone valves that were not installed according to today’s normal piping configurations. Because of the typical design of today’s zone valves, the configuration of the piping for these assemblies requires the flow of gases from left (distribution system side) to right (patient and pressure indicator side). However, the piping of many dated zone valve assemblies flows from right to left.
Because of this opposite direction, the replacement of dated zone valves proves quite challenging. The piping on both sides of the valves must be entirely reversed. This requires a great deal of time (during which the patients in the “shut down” zones must be supplied with reliable, temporary life-supporting gasses), material, brazing gas and labor.
Also, very often the piping must be moved and brazed in very tight places. This is extremely challenging (and sometimes almost impossible) when zone valve piping may be up to 2 inches in diameter!
A solution, which easily eliminates this difficult challenge and enhances patient safety during the shutdown, is the manufacture of and replacement with complete zone valve box assemblies that provide pressure indicator ports on both sides of each valve. The dated zone valves can then be easily replaced with the new ones without altering the piping configuration. After medical gas valves replacement, the installer simply threads the pressure indicator into the port on the patient side of the valve. The ASSE 6000 – 6030 certified verifier then confirms this proper positioning. Also, the additional opening on the distribution side provides a convenient and useful “utility” port immediately adjacent to the valve. This port can be used for blowing out debris or bleeding out Nitrogen NF and then sampling the source gas following a tie-in of a branch tee, etc. This is before opening the zone valve and sending this source gas to the outlets at the points of patient use. The installers who replaced the valves are certified to ASSE 6000 – 6010 and are members of Cleveland Plumbers Local #55. The shutdown technicians are plumbers of Cleveland Clinic’s Facilities Engineering and certified to ASSE 6000 – 6040.
The availability of this type of assembly was discovered after the project was budgeted. Because installation of “dual port” zone valves eliminated the need to reverse the piping of the majority of replaced assemblies, Cleveland Clinic saved tens-of-thousands of dollars on this project. Therefore, the project was completed far under the original budget allowance. Also, now available are “backfeed” fittings that are installed into the zone valve port on the patient side. The required pressure indicator is threaded into the fitting. The fitting also features a CGA gas-specific DISS threaded demand check connection which enables the backfeeding of gas during a planned service interruption, in compliance with ASSE 6000 Annex J. These fittings enhance both ease of use and patient safety.
The typical backfeed method uses wall outlets directly at the point of patient use. Large high-pressure cylinders are positioned intimately at the patient bedside and connected into the outlet, which is usually a “quick-connect” design. Some of the spaces are very confined – such as in intensive care units. Because each backfeed location must be continually monitored, a backfeed technician must also occupy this tight space for the duration of the shutdown.
Also, a parade of “H” cylinders, equipment and technicians in-and-out of patient care areas, such as ICUs, is not an optimal situation. This method is usually fine if the bed space is empty. However, serious logistic challenges are presented if the bed space has a patient – many times with family members present as well. The shutdown technician must work very diligently, in very close patient proximity, monitoring zone pressure and replacing large cylinders, while simultaneously not disturbing the patient and family. Also, there are times when the patients, or their families, express displeasure with having large high-pressure cylinders, regulators, hoses and a strange technician positioned directly in their patient care area with them throughout the duration of the shutdown. Backfeed fittings installed in the zone valve pressure indicator port solves this challenge. This is because zone valves are normally located in hallways or a reasonable distance from the direct patient care areas. Because of their more remote locations, back feeding at the zone valves assures that large cylinders, equipment and technicians are no longer intimately near patients and their families.
Added features of the fitting that benefit the ease of the shutdown are the CGA threaded demand check connection (no chance of the connection becoming accidentally disconnected as is possible with a “quick-connect”) and an observable pressure indicator directly at the backfeed location (which allows for a more-timely pressure adjustment of patient life- supporting temporary gases by the monitoring backfeed technician).
It must be emphasized that before a planned shutdown involving zones that are large or have high volume demands, a preliminary evaluation must be completed to determine if this single port backfeed fitting is capable of providing sufficient amounts of temporary gas to the zone.
In conclusion, regarding this article’s primary theme, because of their much lower total cost regarding simplicity of replacement, “dual port” zone valve assemblies will encourage more healthcare facilities to replace their antiquated, worn out and potentially dangerous zone valve assemblies with modern, fully functional and safer assemblies.
-by Edward Lyczko, IPP, FASSE, Region 6 Director Chair,
ASSE Hospital Systems and Medical Gas Advisory Committee