Analysis of Compressed Air with the Instant Air Check Kit: (update 5/2005)
There are about 3 companies in the US that make air testing kits for checking compressed air systems with color indicator tubes instead of sending a bulk sample to a laboratory. The differences between the kits made by each company are numerous and serious: the number of contaminants that can be tested at one time, pressure control methods, complexity of use, quality of technical support, and cost. Only the kits made by the Drager Corporation, and Analytical Chemists, Inc. (ACI) have the ability to test at least 4 contaminants simultaneously in compressed air, however, the two companies are dramatically different in other capabilities.
An Instant Air Check Kit © is an air sampling kit that can pull a compressed air sample and test that sample on-site for selected contaminants. At this writing, the sampling kits that fall into this category are either based on battery powered electronic meters with a pump and specific sensors, or color indicator tubes. The latter is the non-electronic, more universl, least expensive and most popular approach.
Better? There is nothing better or more thorough in checking air purity than a laboratory analysis. Although color indicator tubes are available for many compounds, they cannot test for everything. Their results are generally sufficient in sensitivity, but are not precise nor as certain as a lab analysis.. There are, however, situations when distance and timing are overwhelming factors. For example, cruise ships or live- aboard boats are seldom near a port that can provide analytical services. The same is true for many islands that have operations which rely on sending air samples to the U.S. to determine if the air is good or not. And then, of course, what does a store or boat owner do when it suspects that the air contains a contaminant such as oil mist, or has to investigate a diver's complaint without a laboratory. With an Instant Air Check kit, one can immediately test the air for the most common contaminants instead of sending a sample to a lab and waiting for the answer. (For a deeper discussion, see Color Indicator Tubes. )
Cheaper? Maybe. The cost of the kits (a one time purchase of hardware) plus the cost of buying more supplies (color indicator tubes and filters) is more expensive than the typical lab fees for just the analysis. However, when the shipping cost, taxes, and duty fees added to off-shore locations, those total fees can become much higher than the actual analytical fees. Despite that, if you factor in time, convenience, logistics and confidence, for off-shore use, the self-test kits are a bargain.
Comparison of Self-test Compressed Air Sampling kits.
Although there are about 5 companies offering color indicator tubes in the U.S., there are currently only 3 companies that make self-test kits: Sensidyne, Gastech, Drager and ACI (Analytical Chemists, Inc.) The Sensidyne and Gastech devices are simple and inexpensive, but can test for only one compound at a time. Moreover, their capability is limited, and they are tedious to use. Moreover, their designs do not meet current Navy, NFPA or ISO1873 sampling criteria. The Drager corporation has at least 4 different compressed air sampling kits which allow a wider range of tests, but they also do not meet the wider scope of all Navy or NFPA requirements. The final player, ACI uses Drager color indicator tubes plus membrane filters and variable air handling capability to make it the only technically correct universal air sampling kit available in the industry. When combined with lab support and lab accreditation, the ACI kit meets all Navy, CGA, NFPA and ISO 1873 requiements. A statement that sweeping requires a closer look a the two manufacturers: Drager and ACI.
The most well known self-test kits are made by the Drager Corporation. Drager offers an AEROTEST SIMULTAN kit for use with HP air, another for use with LP air, and a third kit for pharmaceutical/instrument air. The down side is that their HP and LP kits are not interchangeable. Therefore, if you work with both low pressure and high pressure systems, you would need to purchase both Simultan kits. Both current versions contain a pressure reducer and a flow controlled holder for 4 indicator tubes: CO, CO2, Moisture and Oil mist. Drager also offers a low pressure test kit just for the pharmaceutical industry which can test up to 7 analytes simultaneously.
In contrast, a single ACI Instant Air Analysis kits can sample HP, LP and Pharmaceutical systems. Moreover, the ACI Instant Air Analysis kit can detect particulate and sample up to 10 analytes instead of only 7. Particulate contamination is an important issue, but the Drager kits cannot test for particulate.
The Instant Air Analysis Kits© made by ACI, also use Drager tubes as the analyte detector plus a membrane filter to collect oil mist plus particulate. The patented design of air flow control and dual fail-safe pressure release in the Universal kit allows safe sampling and testing of both low as well as high pressure systems. The kit uses adapters to sample an unlimited variety of air systems. The occasional need for lab analysis is met with small self-purging canisters (300 ml capacity). The kit simultaneously samples up to 10 Drager tubes, one of which concentrates airborne hydrocarbons for off-site lab analysis by GCMS. And it does this in only 5 minutes.
Additional Considerations
Drager tubes are not perfect, and for this reason we include a canister and pre-weighed filters. As mentioned above, the bulk air canisters provide a way for you to submit an air sample for a laboratory analysis. The filters let you see any oil mist or particulate in the compressed air stream, and because they are pre-weighed, they too can be sent to a laboratory for analysis.
The Standard Dedicated Instant Air Check Kit
The comparative summary below shows the differences between the Drager Simultan and the ACI Instant Air Check test kit.
| FEATURES OF COMPRESSED AIR SAMPLING KITS | ACI Instant Air Check test kit |
Drager Aerotest Simultan LP or HP |
| Minimum Pressure needed for a test | 75 | Depends on type |
| Maximum Pressure tolerated | Not Applicable | 130 or 4500 |
| Smallest path in the System | 1/4 inch diameter inlet | Tiny aperture or pressure regulator |
| Flow rate of air through our test kits | < 0.3 to more than 20 SCFM | 0.4 SCFM |
| Number of simultaneous tests at one time | 10 | 7 |
| Large Selection of Adapters | Y | Only SCUBA or SCBA |
| Built-in Safety pressure relief mechanisms | Y | Not Applicable |
| Indicator Tubes: CO, CO2, moisture & Oil mist | Y | Y |
| Bulk Air Sample possible
for lab check of over 50 gaseous and volatile compounds |
Y | - |
| Ability to perform the Oil Mist + Particulate test | Y | - |
| Oxygen Compatible Air Check | Y | - |
| Ability to sample full SCUBA flasks | Y | Y |
| Ability to sample empty SCUBA flasks (with our optional hand pump) | Y | - |
| Minimum Oil Mist
measurement using the kit's depth filter + Lab analysis (mg/m3 ) |
0.005 | - |
| Small portable size | Y | Y |
| Lab Support for sampling kit questions | Y |
Variable |
| Laboratory consultation with chemists | Y |
- |
| Ability to obtain a bulk sample in chambers, closed compartments or elevated air spaces. | Y | - |
** All ACI Sampling
kits (including the Instant Air Check Kits) can sample and test 10 -
4500 psi systems
** All ACI Instant Air Check kits
are custom configured for your business, but the Universal Kit can hold
up to 12 bulk air samples for laboratory analysis.
We configure all kits to meet the client's
needs. The list of possibilities is extensive.
See also Sampling Kits for Sale-Parts List.