raecoblog

Blog of RAECO-LIC LLC, the Midwest US provider for instrumentation to detect, measure, and analyze for process safety and control.

Homepage: https://raecotom.wordpress.com

Sensor drift in gas detectors

Gas sensors drift. It’s not a matter of if, but a matter of when and by how much. When gas sensor drifts, your gas detector might not go off when the gas levels reach a dangerous level, putting you and your employees at risk.

According to OSHA, there are seven factors that contribute to sensor drift:

  1. Degradation of phosphorus-containing components
  2. Degradation of lead-containing components
  3. Gradual chemical degradation of sensors and drift in electronic components that occur normally over time
  4. Use in extreme environmental conditions, such as high/low temperature and humidity, and high levels of airborne particulates
  5. Exposure to high concentrations of target gases and vapors
  6. Exposure of electrochemical toxic gas sensors to solvent vapors and highly corrosive gases
  7. Handling/jostling of the equipment causing enough vibration or shock over time to affect electronic components and circuitry

If your gas detection sensors are exposed to any of these factors, it is important that you calibrate your gas detectors more often and not just bump test them.  (A bump test only confirms that the gas detector can sense that gas is present; it does not tell you if the instrument is still properly detecting low and high levels of the gas or how accurately it’s performing.)

Maintaining your gas detectors shouldn’t be difficult to do. The calibration itself is quick and easy, but this procedure seems to get lost in the shuffle as countless other tasks pile up.

How often do your gas detectors really need to be calibrated? Instrument manufacturers typically recommend that each sensor is bump tested daily and calibrated monthly.

The problem with this recommendation is that it is based on the gas detectors being in a perfectly clean environment that is not too hot, cold, wet, or dry. This is an ideal situation for gas detectors, not a realistic one. The fact is: gas detectors will be placed in all sorts of environments, each requiring a different level of sensor care.

At RAECO, we understand how the calibration process can go wrong or be forgotten altogether. Your employees might not be properly taught the calibration process, or they might be too busy and the procedure gets over looked. If that’s the case, call us!  We’d be happy to take care of your system’s field calibration and make sure you can trust your gas detection systems again.

Want to learn more about our calibration services? Visit http://www.raeco.com/FieldService/

Learn more about portable gas detectors and monitors and fixed gas monitoring systems at RAECO.com

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Webinar Recap: Oxygen Measurement in Safety Critical Applications

In case you missed months’s webinar with Siemens on oxygen measurement in safety critical applications, we’ve put together some of the key points:

What is a safety critical application?

A safety critical application is one in which system failure could result in loss of life, significant property damage, or harm to the environment.

There are a number of critical applications that anyone in the process industry should be aware of:

  1. Thermal oxidizers are process units for air pollution control in many chemical plants. They work by decomposing hazardous gases at a high temperature and releasing them safely into the atmosphere. When thermal oxidizers are not working properly, they can be explosion hazards.
  2. A gas flare is a combustion device used in plants for burning off flammable gas released by pressure relief valves during unplanned equipment overpressure. The oxygen level in the flare gas must be set below that of where an explosion could occur.
  3. Inert blanketing refers to the layer of gas, typically nitrogen, that lays atop contents in a tank, container, or silo to reduce oxygen content in the vapor space, and ultimately reduce the risk of unwanted combustion. If the inert blanketing fails, there is a possibility of explosion.

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Elevated Respirable Particulate Levels on Train Platforms at Union Station

particulate-monitoring-at-union-station

Last summer, the U.S. Environmental Protection Agency conducted an air quality survey at Union Station in Chicago. The results showed elevated concentrations of respirable particulate matter (PM2.5) in ambient air on train platforms and nearby streets.

PM2.5 is a mixture of liquid droplets and particles measuring 2.5 micrometers in diameter or smaller. These tiny particles can be inhaled deep into the lungs where they can enter the bloodstream and cause serious health problems. The risk is even more severe for youth, the elderly and those with respiratory conditions like asthma.

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OSHA Standard 29 CFR 1926 Subpart AA: Construction vs. Maintenance Work

The addition to OSHA Standard 29 CFR 1926 was designed to protect employees engaged in construction activities at work sites with one or more confined spaces.

A confined space is not designed for human occupancy. It has limited means of entering or exiting and can have a potentially hazardous atmosphere. Confined spaces may be poorly ventilated and, as a result, lack adequate oxygen or contain dangerous levels of toxic gases.

Before standard 29 CFR 1926, OSHA’s confined space regulations only applied to general industry. A gap grew obvious when the department of labor statistics reported most confined space fatalities were occurring during construction activities.

The new standard is very similar to the previous one, but applies directly to work in construction. It requires a permit to enter, pre-entry testing and continuous monitoring while inside the confined space.

While this new standard closes the gap in construction work, it leaves out one important component: maintenance.

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How should I sample to comply with OSHA’s silica dust standard?

“So, silica…”dusty

This was how many conversations started while exhibiting at conference  last week. OSHA released its rule for occupational exposure to respirable crystalline silica back in March and many are still looking to understand how it will affect their business and employees.

The new rule goes into effect on June 23, 2016 and most business will have between one to five years to comply depending on industry. The new standard reduces the permissible exposure limit (PEL) for respirable crystalline silica to 50 micrograms per cubic meter of air, averaged over an 8-hour shift. This is a reduction is two to five times lower than the previous PEL.

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