Common Gas Analyzer Questions
- How do I number and identify the outlets in a room?
Many hospitals use the following method to number outlets within a room: As you walk into a room the first outlet on the left is outlet number one. Then go clockwise using consecutive numbers.
- What if all O2 outlets test bad, all have N2 or ??? as the detected gas?
Most likely explanation: The oxygen cell has probably expired. Return the analyzer to NST for calibration and replacement of oxygen cell. If it is less than twelve months since last calibration the oxygen
cell is covered under the manufacturer's warranty.
Most likely problem is particulate matter in valve path. Click here for instructions on how to correct
this problem.
You should bleed the gas line before testing outlets if excess moisture is present in the gas lines. Take a gas adapter for the appropriate type gas and connect it to the outlet without connecting the adapter
to the gas hose. Place your hand in front of the outlet and allow free flow of gas until no moisture appears on your hand. This is not necessary for every outlet. This is a short duration test, a
couple of seconds. Do not perform this test in the presence of an open flame or heating element.
- How does the analyzer test for gas type?
The analyzer tests the percent of oxygen and nitrous oxide in each gas sample run through the analyzer. These percentages are compared to an internally stored data table. The theoretical values for the
different gases are listed in the table below:
Gas Outlet |
Min. O2 % |
Max. O2% |
Min. N2O % |
Max. N2O % |
Medical Air |
19 |
23 |
0 |
0 |
Oxygen |
99 |
100 |
0 |
0 |
Nitrogen |
0 |
1 |
0 |
0 |
Nitrous Oxide |
0 |
0 |
99 |
100 |
Vacuum |
N/A |
N/A |
N/A |
N/A |
The values used by the Gas Analyzer to determine each gas type are listed in the table below:
Detected Gas |
Pressure |
Min. O2 % |
Max. O2 % |
Min. N2O % |
Max. N2O % |
Medical Air |
over 4 PSIG |
10 |
30 |
0 |
30 |
Oxygen |
over 4 PSIG |
70 |
100 |
0 |
30 |
Nitrogen |
over 4 PSIG |
0 |
10 |
0 |
30 |
Nitrous Oxide |
over 4 PSIG |
0 |
10 |
70 |
100 |
Vacuum |
over 1 in Hg |
N/A |
N/A |
N/A |
N/A |
Unknown |
Any gas not falling within the above limits. |
- How many outlets can be tested?
Up to 1500 outlets can be stored in memory before the analyzer display reads "Memory Full". The exact
number varies depending on the number of characters used to identify the outlet location and the number of notes used to supplement the outlet identification.
- How many outlets can be tested per room?
Up to the number 31 can be entered on the display without having to trick the analyzer into thinking testing is
complete in any one specific room. A bank of different types of gas outlets can have the same number. For example, a bank with oxygen, nitrous oxide, medical air and vacuum in an OR can have the same outlet
number, since they can be readily identified by gas type.
- How long does a battery charge last?
With full charge the analyzer can be used for approximately 15-20 hours before recharging. When the analyzer batteries are low the analyzer screen displays "Low Batteries".
Recharging the batteries overnight will bring them back to a full charge. Do not overcharge batteries, as it will shorten the battery life.
- How long does the O2 cell last?
The oxygen cell is warranted for twelve months from installation. Once the oxygen cell is exposed to room air it starts to wear out.
- Degradation of the O2 cell?
The last test before storing the analyzer, for any period of time, should be conducted on an air outlet. Testing
an oxygen or nitrous oxide outlet last allows this gas to remain in the gas-sampling portion of the analyzer, where it can adversely affect the oxygen cell.
- Why does the flow test fail even when there is plenty of flow?
The valve opens to allow flow while simultaneously checking the dynamic pressure. If the pressure drops below the minimum flow pressure preprogrammed in the analyzer, the analyzer records the flow at this
pressure and closes the valve and labels the outlet as BAD for not meeting the specification for flow pressure. To determine the preprogrammed minimum flow pressure see page two "Summary of Explanation of Codes" ,
under the Flow Pressure heading of a report from this specific analyzer.
According to NFPA
99, 1999 edition, a facility needs to check the purity of medical air generated on-site to ensure that the air is pure.
NFPA
99, 1999 edition requires that any system breached must be inspected, tested, and certified as being compliant before being put in operation. There are specific tests that must be conducted by someone other
than the installer of the new system or branch. One of the tests is a test of gas concentration of piped medical gases. The concentration of the gases must meet the following:
Gas |
Concentration Accuracy of Measuring Device |
Medical Air |
19-23% |
Oxygen |
99+% |
Nitrogen |
99+% or < 1% Oxygen |
Nitrous Oxide |
99+% |
- Why isn't the adapter connected to the gas hose being recognized?
If the analyzer does not recognize one of the gas adapters, the resistor within the adapter may be broken.
Call NST to report the problem. If all of the adapters are not recognized, then the most likely problem is a
broken wire in the gas hose. Again contact NST to report the problem. Adapters and gas hoses need to be returned to NST for repair or replacement. |
