A confined space air quality testing equipment holds a very important role in ensuring a safe entry.
As you may already knew that oxygen deficiency, flammable gases, and vapors, and toxic gases are present in a confined space (You can read the previous article about hazards in confined space for more hazards information).
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Besides that, such testing equipment is also used for air monitoring during confined space work in progress.
Because of its importance, confined space air quality testing equipment becomes one of the mandatory equipment in the confined space entry equipment list.
Before showing you the top 3 air quality testing equipment, let’s see some common questions related to confined space gas testing.
What Gases Are Tested in Confined Space?
According to OSHA’s confined space standard 1910.146, the internal atmospheric must be tested before a worker enters a confined space.
The atmospheric testing includes oxygen, toxic gases, and flammable gases, vapors, or mist.
And the testing must use a calibrated direct-reading instrument.
What is The Correct Order of Atmospheric Testing?
The above OSHA’s standard states that the correct order of atmospheric testing are oxygen, flammable gas, vapor or mist, and toxic gas and vapor.
The limit of oxygen, flammability, and toxicity that required confined space permit are shown by the following table.
| Parameter | Permit-Required Confined Space |
| Oxygen | <19.5% or >23.5% |
| Flammability | >10% lower flammable limit (LFL) |
| Toxicity | >50% permissible exposure limit (PEL) or threshold limit value (TLV) |
What Must be Continually Monitored During Work in A Confined Space?
We shall monitor all the above parameters – oxygen, flammability, and toxicity – during a confined space work in progress.
This is to monitor any change that may happen inside it.
If the testing instrument alerts a change, immediately all workers shall move out from the confined space.
Remember that a change may happen due to any reason. Suppose unintended operation of block valve, exhaust blower trouble, pipe leakage, etc.
Best 3 Air Quality Testing Equipment
Okay, now it is time for me to show you the best 3 air quality testing equipment that I took from Amazon.com.
Besides user reviews, I also chose the product based on its features.
Here are the review results:
| Parameter | HZXVOGEN Portable Gas Detector | MULTIGAS Detector | BW Technologies MCXL-XWHM-Y-NA GasAlertMicroClip |
| Analyzed gases | O2 (0-30%) Ex (0-100% LEL) H2S (0-100ppm) CO (0-1000ppm) | O2 (%) Ex (%) H2S (ppm) CO (ppm) | O2 (%) Ex (%) H2S (ppm) CO (ppm) |
| Resolution | O2=1% Ex=1% H2S=1ppm CO=1ppm | O2=0.1% Ex=1% H2S=1ppm CO=1ppm | O2=0.1% Ex=1% H2S=1ppm CO=1ppm |
| Response time | < 30 seconds | < 30 seconds | n.a |
| Battery | 4.2V rechargeable lithium, 1800mAh | rechargeable lithium, 1500mAh | rechargeable lithium |
| Battery life | 10 hours | 12 hours | 12 hours |
| Data logging | n.a | 500 alarm records | n.a |
| Alarm | Intelligent voice broadcast: sound, light, vibration | LED alarm, buzzer, vibration | LED, alarm |
| LCD display | Yes | Yes, colored with graph | Yes |
| USB charger | Yes | Yes | Yes |
| Weight, lb | 2.01 | 0.73 | 0.42 |
| Dimension | 13.5×7.0x2.5 cm | 14.5×6.9×2.8 cm | 11.3×6.0x3.1 cm |
| Waterproof | Yes | Yes | Yes |
| Explosion-proof | Yes | Yes | n.a |
| High temp protection | Yes | No | n.a |
| Dustproof | n.a | Yes | n.a |
| Easy to carry | Yes | Yes | n.a |
| Connect to other gas detectors | n.a | Yes | n.a |
| Customer rating (as of July 19, 2020) | 4.4 of 5.0, 18 reviews | 4.8 of 5.0, 18 reviews | 4.4 of 5.0, 28 reviews |
| More info | Click here | Click here | Click here |
