Page 30 - Occupational Health & Safety, January 2018

OIL & GAS
From Sensors to Data Logging
Most devices with data logging retain monitoring information whenever they are turned on. This can provide useful snapshots of conditions at the time of an accident or unusual event.
BY LARRY MEDINA
There is no such thing as “one size fits all” in the world of safety, especially when it comes to choosing a gas detector. Each work site has a unique set of challenges, and to ensure op- timal safety for on-site workers, selecting a device be- comes a critical choice for many safety managers. With several factors to consider––the gases and vapors po- tentially present on the work site, the areas of risk, fixed vs. portable detectors, etc.––finalizing the “right” safety suite can oftentimes be daunting. Here are a few tips that can help safety managers as they set out to identify the detector that is best suited for their workplace.
Understand the Environment
It’s critical for safety managers to conduct a risk as- sessment to fully understand all aspects of risk on the work site, including if there is a potential presence of combustibles, toxic gases and volatile organic com- pounds (VOCs). Additionally, hazards such as oxygen enrichment—a condition that can cause materials to burn more vigorously than they would under normal circumstances—and oxygen deficiency can impact the device that’s ultimately selected. For example, an influx of inert gases can deplete an area’s oxygen concentra- tion, presenting potential consequences that could hinder mental and physical performance or cause a se- vere loss of consciousness. As such, selecting a device that addresses these conditions becomes critical.
This evaluation testing will determine the neces-
sary steps to ensure that conditions are safe for work. Once evaluation testing has been completed, ongoing verification testing can be done to ensure any and all chemical hazards are below the levels necessary for safe operation.
Sensor Selection
Once there’s been a proper assessment of the surround- ing environment, consider which types of sensors can accommodate the application, and ensure the chosen sensors reflect and address the known and potential atmospheric hazards. In situations where the environ- ment is a confined space, portable gas detectors will often feature a catalytic sensor for the measurement of combustible gases, and one or two electrochemical sensors. Catalytic sensors are useful toward detecting concentrations in the lower exposure level (LEL), the smallest concentration of vapor in air below which a flame will not ignite (even in the company of an igni- tion source), whereas electrochemical sensors are best suited for detecting specific toxic gases. The oxygen reading is the first reading taken in preparation for a confined space entry in order to ensure that there are appropriate oxygen levels, and to also verify that there is enough oxygen for the proper operation of the Ca- tEx sensor.
Other types of sensors include photoionization de- tectors (PIDs), which measure a broad range of VOCs such as methane, benzene, or hydrocarbons that occur
24 Occupational Health & Safety | JANUARY 2018
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