| 3-valve bypass |
A means, via valves, to isolate a
portion of a medical gas system. This typically refers to by-passing
the vacuum / air receiver while still the pumps / compressors are
still running. (note: the vacuum system does not need a 3 valve
by-pass but does need a means to isolate the receiver while keeping
the system functional) |
| absolute
pressure |
Pressure reading taking into
account the ambient pressure. The absolute pressure at sea level is
14.7 psi while the gauge pressure at sea level is 0 psi. The
absolute vacuum pressure reads perfect vacuum as 0" Hg while no
vacuum would be 29.92" Hg. Vacuum read on a gauge is just the
opposite...0" Hg = no vacuum and 29.92" Hg = perfect vacuum.
(absolute pressure is signified by an "a" after the unit of measure
- i.e. 75 psia) |
| Actual Cubic
Feet Per Minute (ACFM) |
Volume of air taking into account
the ambient pressure and temperature. The ACFM value will increase
as the vacuum level - in gauge reading - increases. The deeper the
vacuum, the more space the volume of air takes up. |
| area alarm |
NFPA-99 2005: 3.3.4.1 "A warning
system within an area of use that provides continuous visible and
audible surveillance of Level 1 and Level 2 medical gas and vacuum
systems." |
| ASSE 6010 |
Medical gas installers
professional standard |
| ASSE 6020 |
Medical gas inspectors
professional standard |
| ASSE 6030 |
Medical gas verifiers
professional standard |
| ASSE 6040 |
Medical gas maintenance
personnel professional standard |
| Authority Having Jurisdiction
(AHJ) |
NFPA-99 2005: 3.2.2 "An
organization, office, or individual responsible for enforcing the
requirements of a code or standard, or for approving equipment,
materials, an installation, or a procedure." |
| Bernoulli's principle |
as the speed of a moving fluid
increases, the pressure within the fluid decreases. The fluid can be
a liquid or a gas. For the principle to apply, the following is
assumed:
- fluid or gas flows smoothly
- fluid or gas flows without any swirls or "eddies"
- fluid or gas flows everywhere throughout the pipe
- fluid or gas has the same density everywhere
As a fluid or gas flows through a pipe that narrows or widens, the
velocity and pressure will vary. The fluid or gas will flow more
quickly through the narrow sections, but the pressure will decrease. |
| bulk system |
NFPA-99 2005: 3.3.19 "An assembly
of equipment, such as storage containers, pressure regulators,
pressure relief devices, vaporizers, manifolds, and interconnecting
piping, that terminates at the source valve of oxygen or 1452 kg
(3200 lb) of nitrous oxide including unconnected reserves on the
site." |
| carbon monoxide (CO) |
A colorless, odorless, very toxic
gas and is formed as a product of the incomplete combustion of
carbon. |
| carbon monoxide monitor |
A device that is used to measure
the level of carbon monoxide in the medical air stream. The monitor
is located downstream of the final line regulators. |
| ceiling arm |
(same as ceiling boom) |
| ceiling boom |
A structure mounted to
the ceiling whereby medical gases and electrical
connections can be made. Booms can typically move from side to
side around the patient. Ceiling booms are found in surgical areas
or ICU’s. |
| ceiling column |
A structure mounted to
the ceiling whereby medical gases and electrical connections
can be made. Any movement of the column is only up and down. There are (3) types of ceiling columns: fixed (or rigid), manual retractable, or powered retractable. Ceiling columns are typically
found in surgical areas or ICU’s. |
| Charles Law |
volume of gas increases or
decreases as the temperature increases or decreases - providing the
amount of gas and pressure stay fixed. volume divided by temperature
= a constant (or a linear relationship).
V1 / T1 = V2 / T2
(note: absolute zero is found via Charles law. That is the
temperature at which a volume of gas gets cold enough to be reduced
to a theoretical volume of zero. Absolute zero is -460°
F or - 273° C) |
| cryogenic |
Of or relating to very low
temperatures. Bulk medical gases are shipped and stored on site as
liquids. To achieve the liquid stage, the gas must be very cold.
Vapor forms as the liquid warms up. A gas is cryogenic, by CGA
standards, if it is colder than -100° F |
| cryogenic system |
(same as a bulk system) |
| Dalton's law |
the total pressure of a gas
mixture is equal to the sum of the partial pressures of each
individual gas |
| desiccant |
A drying agent that has affinity
for water. It may be silica gel, activated alumina, or other
materials. |
| desiccant dryer |
A system of chambers, valves, and
switches that utilizes desiccant to dry the air. |
| dew point |
The temperature at which vapor
begins to condense. |
| dew Point
monitor |
A device that is used to measure
the level of moisture (measured as dew point) in the medical air
stream. The monitor is located downstream of the final line
regulators. |
| filter bank |
A series of valves, filters, and
regulators that are found in a medical air system. |
| flow meter |
A device used to regulate the
flow of medical gases - typically oxygen and air. Flow meters are
found in the patient rooms and are affixed to the medical gas wall
outlets via gas specific adaptors. |
| galvanize |
To coat with Zinc. Medical air
and instrument air receivers are required to b corrosion resistant.
One way to achieve this is to dip the receiver in zinc prior to
fabricating the system. |
| gauge pressure |
Pressure reading not
taking into account the ambient pressure. The gauge pressure at sea
level is 0 psi while the absolute pressure is 14.7 psi. The gauge
vacuum pressure reads perfect vacuum as 29.92" Hg while no vacuum
would be 0" Hg. Vacuum read on an absolute scale is just the
opposite...0" Hg = perfect vacuum and 29.92" Hg = no vacuum. (gauge
pressure is signified by a "g" after the unit of measure - i.e. 75
psig) |
| halogenated agents |
To treat or caused to combine
with a halogen. A halogen is any of the (5) elements of fluorine,
chlorine, bromine, iodine, and astatine that form part of group VII
A of the periodic table and exist in the free state normally as
diatomic molecules. |
| headwall |
A prefabricated unit consisting
of medical gas outlets / inlets, electrical outlets, and brackets
used to mount other medical items. |
| hyperbaric |
NFPA-99 2005: 3.3.73 "Facility,
building, or structure used to house chambers and all auxiliary
service equipment for medical applications and procedures at
pressures above normal atmospheric pressures." |
| hypobaric |
NFPA-99 2005: 3.3.75 "Facility,
building, or structure used to house chambers and all auxiliary
service equipment for medical applications and procedures at
pressures below normal atmospheric pressures." |
| Inlet Cubic Feet Per Minute (ICFM) |
measurement of a volume of air
taking into consideration the ambient temperature and pressure.
Typically this is used to refer to the volume of air a medical air
compressor system can produce. The ICFM value will change as the
temperature and pressure of the ambient conditions change. |
| in-line valve |
Optional valves used to isolate
specific rooms or areas (see NFPA-99 2005: 5.1.4.9) |
| instrument air compressor
system (per NFPA-99) |
NFPA-99 2005: 5.1.3.8 “For the purpose of
this standard, instrument air is air intended for the powering of
medical devices unrelated to human respiration (e.g., surgical
tools, ceiling arms). Medical air and instrument air are
distinct systems for mutually exclusive applications.” |
| Joint Commission on
Accrediting Healthcare Organizations (JCAHO) |
Agency which evaluates and
ultimately accredits (hopefully!) medical facilities. JCAHO
evaluates a facilities compliance with their standards. The Joint
Commission is governed by a 29 member board of commissioners. |
| latent heat |
Heat given off or absorbed in a
process, as fusion or vaporization, other than through a change in
temperature. (water = 1,050 BTU per pound....BTU = the heat required
to raise the temperature of one pound of water one degree
Fahrenheit) |
| level I system |
NFPA-99 2005: 3.3.90 "Systems
serving occupancies where interruption of the piped medical gas and
vacuum system would place patients in imminent danger of morbidity
or mortality." |
| level II system |
NFPA-99 2005: 3.3.92 "Systems
serving occupancies where interruption of the piped medical gas and
vacuum system would place patients at manageable risk of morbidity
or mortality." |
| level III system |
NFPA-99 2005: 3.3.94 "Systems
serving occupancies where interruption of the piped medical gas
would terminate procedures but would not place patients at risk of
morbidity or mortality." |
| local alarm |
A visible and audible indication
of the operation status of a piece of equipment. This alarm should
be on or in the immediate area of the equipment it monitors. |
| mainline valve |
A main supply line valve, located
just inside the facility. A Mainline valve is not required if the
source valve is accessible from within the facility. (see
NFPA-99 2005 5.1.4.5) |
| master alarm |
An alarm which audibly and
visually indicates the status of the source equipment (i.e. medical
air compressor, bulk oxygen system, etc) and the facilities mainline
pressure. Each facility is required to have (2) master alarms. One
in the area of the person responsible for maintaining the medical
gas and vacuum system and the other in an area of continuous
observation, such as a switchboard or security office. |
| medical air compressor system |
A series of
compressors, an air receiver, dryers, filter banks, etc. The system
will not add any contaminants to the air stream. Medical air is only
used for patient care. The operating pressure is typically 50 -55 psi. (see NFPA-99 2005 5.1.3.5) |
| medical gas adaptor |
a device affixed onto a secondary
piece of equipment (flow meter, vacuum regulator, etc) that allows
the secondary device to be inserted into the medical gas outlet /
inlet. The adaptor must match the keying style of the medical gas
outlet / inlet. (see "gas outlet style" section) |
| medical gas manifold |
a piping network of valves,
gauges, and regulators that allow the dispensing of a particular
medical gas at the correct pressure. Most manifolds are housed in an
enclosure. |
| medical gas outlet |
A device to dispense
medical gases (or an inlet for medical vacuum) that includes
check valves (one check valve for vacuum) and is gas specific so
that secondary devices cannot be “attached” to the wrong gas. (see
NFPA-99 2005 5.1.5) |
| medical vacuum system |
A series of vacuum pumps, an air
receiver, etc where a negative pressure is created so that
suction may be used in surgical or patient rooms. The medical vacuum
pipelines should be “dry” with no patient waste sucked into the
pipelines. (see NFPA-99 5.1.3.6) |
| nitrogen control
cabinet |
Cabinet, usually found in an OR
or ER, used to regulate and control the pressure of nitrogen to the
surgical tools. |
| partial vapor pressure |
vapor pressure = the pressure of a vapor in equilibrium with its
non-vapor phase. (e.g. when water evaporates, the vapor pressure
exerted by the evaporating water). The partial vapor pressure would
be the pressure of (1) individual gas in a mixture. The sum of the
partial pressures = the total vapor pressure of the mixture (this is
Dalton's law) |
| pedestal |
A structure mounted to the floor
whereby medical gases and electrical connections can be made.
Pedestals are fixed and cannot move up or down. Pedestals are
typically found in Cath labs. |
| refrigerated dryer |
a means to dry air which utilize
a refrigerant to cool the passing air stream and ultimately "wring
out" a large portion of moisture in that air stream. |
| relative humidity |
the amount of water that is present in the air compared to the
greatest amount it would be possible for the air to hold at that
same temperature. |
| riser valve |
A valve located on each riser as
the riser branches off (and up) from the mainline. (see NFPA-99 2005
5.1.4.6) |
| secondary device |
any device that a care giver
would "plug into" a medical wall outlet (i. e. flow meter, suction
regulator, etc) |
| service valve |
A valve located on a lateral
branch of a main or riser. They are used in case the specific
area needs to be shut down without shutting down the entire main or
riser. (see NFPA-99 2005 5.1.4.7) |
| source valve |
A shut off valve located
immediately after the complete source system. If this valve is
closed it would cut off the supply of gas to the entire facility.
(see NFPA-99 2005 5.1.4.4) |
| Standard Cubic Feet Per Minute
(SCFM) |
Volume of air based on standard
atmospheric conditions (68° F,
sea level or 14.7 psia, and 36% relative humidity) SCFM allows one
to use a "standard" volume of air as a comparison for two or more
vacuum pumps or air compressors. |
| suction regulator |
a secondary piece of equipment
used to reduce the vacuum level coming out of the wall (actually
being sucked into the wall). The care giver can change the vacuum
level based on the patients needs. |
| type K copper |
The "heaviest" or thickest (as
classified by ASTMB88) of the (3) copper typed used in medical has
piping. |
| type L copper |
The "standard" or medium
thickness (as classified by ASTMB88) of the (3) copper typed used in
medical has piping. |
| type M copper |
The "lightest" or least thick (as
classified by ASTMB88) of the (3) copper typed used in medical has
piping. |
| vacuum regulator |
(same as suction regulator) |
| Zone Valve |
Valve(s), typically found in
hallways, used to shut off gases in case of an emergency. They will
shut off gas flow only to the floor or area they serve. Zone valves
are usually mounted in a zone valve box which include a gauge. Each
valve must be labeled for the area they serve. (see NFPA-99 2005
5.1.4.8) |
