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Questions
& Answers
I've seen installers put a wet rag on the pipe while they are
brazing. Why do they do this?
The bottom line is to keep the high heat from the torch off of valve
or outlet sealing materials. The high heat from the torch can melt
the ball valve or medical gas outlet internal sealing surfaces.
This is an example of a common installer mistake when brazing
medical gas outlets: If the installer does not wrap a wet rag around
the pipe he / she is brazing, the soft check valve inside of the gas
outlet will melt. When the pipe pressure test is done, the outlets
will leak. This is not a defective outlet, but rather poor brazing
techniques! |
Why is there always ice on my bulk oxygen system?
Ice on your bulk oxygen system is normal. The liquid oxygen in the
tank is very cold (less than -100° F). Before
the vaporizer, the oxygen may even still be in the liquid state!
Obviously, this cold liquid / gas will in turn cool the pipe it's
running in. The moisture in the outside, atmospheric air, as it
touches the pipe, will condense and then freeze on the pipe. This
will hold especially true on humid days. You will notice the
freezing will be at the point where the pipe exits the tank and goes
into the vaporizer. Ice will be on part of the vaporizer but not all
of it...after all, it's the vaporizers job to warm the liquid oxygen
so it changes into a gaseous state. If there is ice all over the
vaporizer, your vaporizer is too small! A little bit of ice is
normal, but it may be a good idea to "knock" the heavy ice off of
valves, etc as the ice can get heavy and potentially damage
equipment. |
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I found this article and thought I'd put a link here. Please be
careful when breathing air from a compressor http://www.cdc.gov/niosh/FACE/In-house/full9131.html |
Will (1) area alarm panel be enough for 10 operating rooms on 1
floor? (We do have N2O)
Yes, one area alarm panel is enough. The installer / engineer has to
ensure that the sensors for the area alarm are picking up the
pressure of the gases BEFORE the zone valve boxes though. You must
have a zone valve box outside of each the (10) OR's, so the area
alarm sensors must be on the lateral branch before any of the zone
valve boxes. This is only allowed when nitrous oxide is being used.
On a side note, the 2005 edition of NFPA-99 now allows the area
alarm sensors in an anaesthetizing location to be located before
or after the zone valve box (previous editions
only allowed the area alarm sensors before the zone valve box). In
the scenario above, if the installer / engineer wanted the area
alarm sensors located after the zone valve box, you would need (10)
area alarms...one for each zone valve box! |
I've heard Nitric Oxide mentioned before - what is it? Can you
tell me a little bit about this gas?
Let me first say that I am not a doctor. If you want more medical
information regarding nitric oxide, please consult a qualified
physician. With that said, Nitric Oxide (or NO) is a gas with one
molecule nitrogen and one molecule oxygen. Nitric oxide is a
soluble, highly reactive gas. Because it is small and diffusible, NO
passes through cell membranes and is often used as a biological
signal. NO also assists the body's immune system and also dilates
the blood vessels, which in turn helps maintain blood pressure. (I'm
sure you've heard of Viagra - NO dilates blood vessels allowing more
blood to flow. More blood flow means...I'm sure you know what
increased blood flow leads to!)
In our brains, NO plays a vital role in developing the brain and
neuron to neuron signaling. There is virtually no pathological
condition where NO does not play a role (sunburn, learning
disorders, diabetes, stroke, etc, etc). As we age, our cells appear
to produce less and less NO.
NO can also inhibit the bodies consumption of oxygen. Although a
vital ingredient in the bodies normal operation, NO can be fatal if
too much is administered. NO is not a gas that would be centrally
piped within a medical facility...don't even ask a medical gas
products supplier for a NO manifold!
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Why does the lag alarm on my vacuum
system come on even though I’m confident the system is not too
small?
First, there may be numerous reasons why this is so (artificial leak
in the system, motor starter not engaging, etc) but a common cause is
the improper setting of the vacuum switches. Via shipping or the
normal “shake” of a system, the switch settings may deviate from
their factory settings. If the low switch setting (switch closes) of
switch #2 is set at or above the low point of switch #1, the lag
vacuum pump will start, sounding off the lag alarm. (the same will
be true for triplex system...if the low point of switch #3 is set at
or above the low point of switch #2) Consult the manufacturers
switch settings and make sure the high and low set points of all
switches are correct.
The second most common reason for an inadvertent lag alarm is a
blown control relay. If the relay that opens and closes the vacuum
switch contacts for the lead pump is blown, the 1st pump will not
start...necessitating the starting of the 2nd pump and the lag alarm
will sound. (triplex and quadraplex systems can be affected as well
but a blown relay may or may not cause the lag alarm to sound)
This same principle will hold true for medical air compressor
systems as well! |
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Can I power my ceiling arm from the
medical air source?
No! Previous versions did allow for medical air to power ceiling
services, etc; however, the latest NFPA-99 version specifically
states that medical air can only be used for human respiration or
for the calibration of medical devices for respiratory application.
(see NFPA 99 2005 5.1.3.5.2). If a pneumatic power source is
required for ceiling columns, it must be a completely separate
system from the medical air supply. Typically columns and surgical
tools are powered by nitrogen or instrument air (see NFPA 99 2005
“definitions” 3.3.80) |
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What are the proper floor to product
heights for medical gas items?
This site has a section dedicated specifically to that question (see
the section to the left of the main page titled: "mounting heights
for products"). The product heights are determined so that care
givers can readily access the necessary equipment and at the same
time try to keep the products out of the way. Some common products
and their typical heights from the finished floor are:
medical gas outlets - 60" on center
zone valve boxes - 66" to the top of the box
master & area alarms - 66" to the top of the alarm |
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Is NFPA 99 law?
Well yes and no. NFPA 99 standards are recommendations for minimum
requirements of product construction, installation and testing of
medical gas systems. There is not a federal law that mandates
compliance; however, individual states or local jurisdictions may
adopt all or parts of NFPA 99. If this is the case, then the parts
of NFPA 99 that the states or local jurisdictions have adopted must
be adhered to. |
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I'm confused about the various medical
gas outlet keying styles – what do I have?
This is probably the #1 issue of confusion in our industry. (a
whole section has been dedicated to this topic. See "gas outlet
styles" on left hand column) There are (4) main types of medical gas
outlets. What makes this very confusing is most manufacturers make
all (4) keying styles. So....you may have an Ohio keyed outlet but
made by Chemetron or a Chemetron keyed outlet made by Ohio! Now you
can see why it's confusing! The (4) main keying styles are as
follows:
1.) Diameter Index Safety
System (DISS)
2.) Ohio / Ohmeda
3.) Chemetron (or Allied)
4.) Puritan-Bennett |
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Can a refrigerated dryer dry my medical
air below 32° F?
Yes if the dryer is functioning properly and has close to the
dryers designed flow passing through it.
NFPA-99 2005 dictates that the dew point level shall be measured after
the final line regulator...at 50-55 psi. At this reduced pressure level, a
refrigerated dryer can dry the air to a dew point level well below 32° F.
This is due to the fact that as the air is reduced in pressure (from 100 psi
to 50 psi) the air expands. As the air expands, the dew point level will
always drop. It's important to ensure that the dryer has close to its designed
air flow feeding into it. This holds especially true with non-cycling dryers. (i.e a 50 CFM dryer is designed to have 50 CFM of
air flowing through it). |
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If I do minor repairs to a piece of
equipment, do I have to re-certify the whole system gas system?
If you do minor repairs, (e.g. replacing a broken motor, change
belts, light bulbs, etc) you do not need to have the medical gas
system certified. If your repairs require that you cut into the
medical gas pipeline or replace a major component such as an alarm
or outlet, then you must have the system certified. When in doubt,
consult with a qualified ASSE 6030 verifier in your area. |
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Can I run my waste anesthetic gas and my
patient vacuum through the same vacuum system?
This is an area that has sparked good conversation as of late. Yes,
both anesthetic waste gas and surgical suction may be supplied by
the same source. There is concern that new anesthesia machines may
induce higher levels of oxygen into the medical suction lines. This
website makes no determination as to proving or disproving the
theory that these machines may elevate the oxygen level in a piped
medical gas systems to dangerous levels, resulting in a catastrophic
failure when using a lubricated oil sealed pump.
If one chooses to utilize a system dedicated to the removal of waste
anesthetic gases, then that vacuum system must be designed of
materials and sealants that are inert in the presence of oxygen,
nitrous oxide, and halogenated agents.
Keep in mind that a venturi system is acceptable as long as the
venturi is driven by water, inert gas, instrument air, or another
dedicated air source. Medical air shall not be used to power the
venturi.
It is wise to consult with a qualified supplier of medical gas
vacuum systems before specifying or purchasing a new vacuum system. |
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If the foreman of the medical gas
installation crew has his ASSE 6010 medical gas installers
certification, can anybody on his crew braze the medical gas piping?
No! Every person who is brazing the medical gas pipeline should each
have their own ASSE 6010 medical gas installers certification. This
is to ensure that the pipeline infrastructure is properly brazed no
matter who is holding the torch. |
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I heard a conversation about various
medical facility "levels," what does that mean?
NFPA-99 has broken down various facilities that may have piped gas
and / or vacuum systems into three "levels" or categories. Taken
verbatim from NFPA-99 2005 they are:
Level 1 Medical Piped Gas and Vacuum Systems "Systems
serving occupancies where interruption of the piped medical gas and
vacuum system would place patients in imminent danger of morbidity
or mortality."
Level 1 Vacuum System "A system consisting of
central-vacuum-producing equipment with pressure and operating
controls, shutoff valves, alarm warning systems, gauges, and a
network of piping extending to and terminating with suitable station
inlets at locations where patient suction could be required."
Level 2 Medical Piped Gas and Vacuum Systems
"Systems serving occupancies where interruption of the piped medical
gas and vacuum system would place patients at manageable risk of
morbidity or mortality."
Level 3 Piped Gas System "Systems serving occupancies
where interruption of the piped medical gas would terminate
procedures but would not place patients at risk of morbidity or
mortality."
Level 3 Compressed Air System "A system of component
parts, including but not limited to, air compressor, motor,
receiver, controls, filters, dryers, valves, and piping, that
delivers compressed air <110 kPa (<160 psi gauge) to power devices
(hand pieces, syringe, cleaning devices, etc.) as a power source."
Level 3 Piped Vacuum System "A level 3 vacuum
distribution system that can be either a wet system designed to
remove liquids, air-gas, or solids from the treated area; or a dry
system designed to trap liquid and solids before the service inlet
and to accommodate air-gas only through the service inlet." |
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Our facility is well above sea level.
Should I be concerned about our elevation when buying a new vacuum
system?
Yes. When purchasing a vacuum system altitude must always be
considered. The general rule of thumb is: for every 1,000 feet in
elevation the vacuum pump loses 1" Hg. Let me explain: perfect
vacuum - at sea level - is 29.92" Hg gauge. A typical lubricated
rotary vane pump can achieve a vacuum level of approx 29" Hg gauge.
If your facility were 1,000 feet above sea level, that same
lubricated vacuum pump would only be able to achieve 28" Hg gauge.
This is due to the elevation...the air is already under a 1" Hg
gauge vacuum. If you are 6,000 feet above sea level, that same pump
can only achieve a maximum vacuum of 23" Hg gauge. Typically, the
vacuum switch settings on a duplex system will be set at: PS-1 18" -
23" and PS-2 17" - 22". At 6,000 feet, the pumps maximum vacuum
level is 23"! If a triplex or quadraplex system is required, the
maximum high and low vacuum switch settings get "squished" (i.e. you
only have approx. 15" to 23" to set 3 or 4 vacuum switches.)
A medical air compressor system will also be affected by altitude
but not to the degree that at vacuum system will. For example, at
6,000 feet above sea level, an air compressor system will need to be
upsized approx. 10% to compensate for the higher altitude.
Bottom line, consult with a qualified engineer and or a reputable
medical gas system supplier before purchasing equipment.
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