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WAGD
Information
Waste Anesthetic Gas Disposal (WAGD) is getting a lot of attention
recently. There are a number of
points that should be clarified about WAGD systems:
1.) Waste anesthetic gas can be drawn by a dedicated vacuum (used only to
draw from WAGD inlets) or waste gas can be drawn by a medical /
surgical system where (1) vacuum system can be used to pull waste
gas and provide surgical suction. If you choose to only use (1) vacuum
system in your facility, do not forget to size the system to include the
extra volume of air that will be needed for the WAGD requirements -
typically 1.0 SCFM per room.
2.) If you choose to have a vacuum system dedicated to only waste gases
(with a 2nd system for surgical suction), the system must be: "Designed of
materials and using lubricants and sealants that are inert in the presence
of oxygen, nitrous oxide, and halogenated anesthetics." (NFPA-99 2005
5.1.3.7.2.1(2))
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When there are oxygen levels that are very high - as
is the case with a dedicated WAGD system - you cannot let the waste
gases come in contact with hot oil or fire may occur. This is why the
system must be designed using inert materials, lubricants, and sealants.
The question has been raised whether a dual system (where (1) vacuum
system is used for both surgical suction and WAGD) should be of inert
materials and lubricants also. Some say that due to new anesthesia
systems on the market that exhaust more oxygen, etc in the vacuum line,
blending waste gases into the surgical vacuum pump will elevate the
oxygen levels to potentially dangerous levels. Others say the elevation
is minor and that there are thousands, possibly even tens of thousands
of systems that have been used in this manner over the years. There is
no doubt that this will be a point of discussion for many years to come.
3.) If you have a dedicated WAGD system, the piping infrastructure must be
designed just like a surgical vacuum system. That is to say that the
dedicated WAGD system shall have a main line / source valve, mainline low
switch, gauge, and all necessary valves / zone valve boxes. In addition, it
needs to have a local alarm, be tied in to the master alarms, and have
appropriate area alarms as well. It needs to be treated just as it is...a
stand alone medical system.
4.) If you have a dual source system (where (1) vacuum system is used for
both surgical suction and WAGD), the WAGD portion (where the surgical vacuum
piping is "T'd" and the WAGD system begins), must have all the necessary
valves, alarms, etc per NFPA. One can "T" into the medical vacuum system at
any point, (actually must be 5 feet from the vacuum inlet) but everything from the "T" in point to the patient side must
have the required valves, alarms, etc. (example "A" - if the WAGD system is
"T'd" on the patient side of the source valve... the WAGD system must have
its own piping, mainline low switch, gauges, riser valves, zone valves, and
alarm connections all the way to the WAGD inlets. Example "B" - the WAGD is
"T'd" on the patient side of the zone valve box... the WAGD need only be
piped to the inlets - remember that for a surgical area, the area alarm is
on the source side of the zone valve box.
If you have any questions or comments, please email us!!!
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