Page 35 - Occupational Health & Safety, April 2019

be evaluated before entry to the space (pre- entry checks), during entry (continuous), and when an entrant exits the confined space and re-enters. Gases stratify based on their weight, and depending on the gas compound, there can be a stratification ef- fect of gases sinking or rising in a confined space. A gas detector with a pump should be used to evaluate the quality of the air at a distance from the entrant.
Whenever using an instrument with a pump, the user must wait for the gas to reach the sensor. Sample time is two sec- onds per foot of tubing attached to the pump, plus two minutes per location (mea- sured at 4-foot intervals).
What are the most common con- fined space entry mistakes you see? A very common mistake is inadequate sample time. The entrant is in a hurry to get the work done because time is money. They rush into the confined space to dis- cover the environment was not adequately ventilated, resulting in more lost time repo- sitioning equipment.
As a trainer, what are some of the most concerning questions you get about monitoring gas in confined spaces?
The most common ones are, “Do we have to wait that long to get an accurate gas sam- ple?” or “I’ll be done in a few seconds, why should I have to wait? I can hold my breath that long!”
One time, someone asked, “How thick should the rope be that I tie my instrument to, quarter inch, 3/8”, para cord?” Lowering a gas detector by rope is not recommended because the instrument can become dam- aged and you can’t see the readings when the device is inside the space. Always use a length of sample tubing with a pump and follow the 2 by 2 rule.
How is confined space monitoring changing with new wireless gas detection technology?
Wireless technology can be a game changer for confined space entries by notifying the attendant of changes in the environment before the entrant is aware of the change. Features such as motion control (man down) notify the attendant of a downed co- worker, and the attendant then can notify rescue services. Some wireless gas detectors
will allow you to view the screen of another gas monitor (such as within a space), al- lowing entrants to understand the environ- ment before work or rescue.
Wireless beacons that assign sites help to identify specific locations where workers are or have passed through. This is helpful in locating a fallen worker. In combination with an area monitor, beacons are also help- ful in identifying rogue gases coming from a plant process and can help save money by reengineering the process to capture the rogue gas.
Gas detectors with cell, wifi, and Blue-
tooth connectivity provide another set of eyes on lone workers. Workers at off-site facilities are monitored for motion control and gas exposures. Supervisors can receive text messages and emails that identify who may be in trouble and unable to call for emergency services.
All in all, wireless technology can im- prove response times when a confined space incident occurs and improve safety for first responders.
Joe Buckley serves as a gas detection profes- sional trainer at Industrial Scientific.
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