A refinery has a large explosion, and the site must be evacuated. In addition to the company’s own employees, there are hundreds of contractors on site. Everyone is required to report to a muster area. Since the workers are all wearing hydrogen sulphide (H2S) gas monitors that are connected through wireless technology, the safety team will quickly be able to assess whether everyone has arrived at the muster point safely.
“A lot of things on the administrative side are not immediately available in an emergency response,” says Nick Randall, technical sales specialist at Calgary-based Concept Controls. “When all these devices are interconnected, it’s a matter of just logging into the software and seeing where everyone is.”
In recent years gas detectors have become much more than devices to detect the presence of hazardous gases. Wireless, “connected” technology has transformed them into platforms for a variety of functions. Many of these features are useful to safety managers, but it is also important to be aware of the limitations of these new devices.
Gas detectors are designed to measure and identify the concentration of certain gases in certain work areas. Typically, they protect workers from exposure to flammable gases, toxic gases and low oxygen concentrations. Detectors are equipped with one or more sensors, which each have a certain life expectancy.
Use of gas detectors is highest in industrial facilities and is most common in industries such as oil and gas (offshore platforms, onshore refineries and chemical plants), natural gas facilities, steel mills, printing plants, construction, mining and utilities. Cable and phone companies equip their workers with hydrogen sulphide and carbon monoxide (CO) detectors before going into manholes.
Gas detectors are also used in commercial buildings and public facilities, such as retail centres, schools and swimming pools. Flammable detectors are used in restaurants. In office buildings, gas detectors measure oxygen and carbon monoxide content, and in parking garages, there are detectors monitoring carbon monoxide levels.
Gas detectors have advanced in recent years through the introduction of new sensor technologies, says Michael Douglas, national manager, market segments, at Oakville, Ont.-based Levitt-Safety. For example, infrared gas detection is used today to detect combustible hydrocarbon gases. Photo-ionization detectors (PIDs) use ultraviolet rays to detect volatile organic compounds (VOCs) such as solvents, fuels, degreasers and lubricants, which are used in manufacturing processes and waste handling.
Moreover, a single gas monitor today can detect many different hazardous gases.
“Back in the coal days of Pennsylvania, LEL (lower explosive limit) monitors were basically looking for methane. They graduated into adding more sensors. You had to buy an oxygen detector and flammable detector separately, and then they combined them into one unit. Then they started adding toxics like carbon monoxide, hydrogen sulphide and chlorine. They evolved into three-gas, four-gas units. Now, with some gas detectors, you can detect up to seven different things with one unit,” Douglas says.
The biggest change in gas detection today, however, has been the trend among manufacturers to move their products into cloud-based systems, he says. This technology allows a company to manage its gas detection program remotely.
Cloud-based systems centre on what is called a docking station. Gas detectors need to be calibrated, a procedure in which a person presents an amount of the hazard to the detector to make sure it is working correctly. Typically, this task is performed by the company that owns the detector. Through the docking station, manufacturers remove this function from the user company. At the end of every shift, each detector is placed into a station, which is connected both to the cloud and to the manufacturer, which can then monitor the detector.
“What the manufacturer can do through predictive technology is to understand, for example, that this particular gas detector has a sensor that is about 25 per cent of the way through its life, and this other one is 75 per cent of the way through its life. So, they will send a replacement sensor for the one that’s at 75 per cent directly to the end user (the employer). It will arrive at the end user, and the end user will do the change and send back the old sensor. The manufacturer may even send a brand-new instrument,” Douglas says.
Manufacturers are also incorporating different types of communication protocols into the devices themselves. With this added technology, which may be proprietary, cell or Bluetooth, they can track the unit as it moves through a work site.
“Manufacturers are using that type of technology for various reasons, including the collection of data: how their instruments are being used, what the gas monitor is ‘seeing’ in the way of blips on the various sensors. They want data about each alarm: Is it a high-level alarm, a low-level alarm? Was it ignored, was it acknowledged? Did the alarm persist after it went off? For how long?” Douglas says.
“Employers don’t want their workers to stay in that alarm condition; they want them to move to a safer area. So, that’s all good data to return back to the employer, especially if people are ignoring alarms.”
To their connected detectors, manufacturers have also added other features. One of these is a man-down alarm. If a worker has a medical incident, for example, is incapacitated and stops moving for 30 seconds or a minute, an alarm will be triggered. This feature is particularly useful for lone workers, where no one else is around to help. The alarm could be broadcast to the supervisor’s cellphone or go to a control room in the facility where someone monitoring a screen could summon an emergency response.
Another feature, Douglas adds, is the ability to link or connect a team of workers through the detectors. In this situation, if an alarm goes off for any member of the team, everyone in the team will see the alarm, know whose alarm went off and what type of hazard, such as low oxygen or flammable gas, set off the alarm. If the endangered worker does not respond quickly, any other person on the team can initiate a response to help the worker.
Randall of Concept Controls says the trend to integrate detectors with other devices and functions is increasing safety awareness. Today, instead of downloading a data record every few months, a safety manager can get the readings in real time and often with localized GPS maps and will be able to see exactly where a worker was when their monitor detected a higher gas level. A company may be able to cordon an area off or shut off a valve or vent that may be the source of a leak.
“With the data they get now, safety managers can ask, ‘Why are we getting more gas detection in one area of the plant, or of the job, than in others?’ It’s about tying in the process controls with individual gas detection readings. Companies have found that the information that tells them where there are spikes in gas detection, what areas of a plant or of the job process, helps them engineer safety solutions based on those gas detection readings,” he says.
“Twenty years ago, a gas detector was: ‘Am I going to walk into a dangerous area?’ Today, with the integration, it’s not only that but also ‘Where are our problem locations across our work areas?’ So managers can then adapt to those situations, instead of being reactive to an alarm.”
Many manufacturers are using Wi-Fi technology or Bluetooth connected to a smartphone in their gas detection systems. One manufacturer that is using Bluetooth to extend the functions of gas detectors is Honeywell. The SensePoint XRL, used in industrial applications to detect toxic gases or explosive gases, is a fixed detector that allows users to connect with it through a smartphone or tablet, says Jason Knudson, product manager, industrial, at Fort Mill, S.C.-based Honeywell Safety and Productivity Solutions.
Workers can connect from up to 10 metres away to perform maintenance tasks, such as calibration. Since fixed gas monitors are often mounted high off the ground, the ability to manage these tasks remotely is much safer and keeps workers away from possible hazardous gas near the monitors. It also makes maintenance easier.
“Traditionally, you would interface with a fixed-point gas detector by going up to it and interacting with it directly with a magnetic wand and with switches on the device. You would have to go through some menus and screens to get to the information. It takes time,” Knudson says. “We’re trying to improve the user experience with the gas detectors.”
With the SensePoint XRL, released in 2017, safety managers can produce system reports. By selecting the desired report on the app, they can get a maintenance report on a particular detector, for example, or a gas history report that may be needed for a safety audit. Honeywell has also added Bluetooth to its portable detectors.
Calgary-based Blackline Safety is using a different technology. The company’s G7 monitors have cellular radio embedded in the device, says Brendon Cook, chief technology officer and co-founder. A connection with a smartphone is not required, which can be an advantage since cellphones are often banned from work areas, he adds.
The monitor has features useful for lone workers as an employee’s safety can be monitored continuously. When the person’s device detects an incident such as a fall or lack of movement, it will trigger an alert that is sent to a monitoring team who manages the emergency.
“With a person-worn detector, we can capture a gas-based exposure, of course, and drive that through to a live monitoring team as an alert. But also, if a worker misses a required check-in — say they’re on an hourly check-in schedule — that can be communicated to the monitoring team,” Cook says. “It’s a real-time emergency response management system.”
The communication link is maintained for employees who not only work in different areas across one site but also travel from site to site.
“As they journey from one location to another, they can remain wirelessly connected,” he says.
The system can also be used to automate the testing regimen a company needs to demonstrate its compliance with regulations. The system will stream the bump tests (usually performed every day or two), the calibrations (done once every three to six months) and employee usage to the online software.
“Instead of people having to go into the field, retrieve data logs from docking stations and compile a report on it, we automate that whole process. It saves businesses a lot of time and energy, and there is no compliance gap,” Cook says.
The G7 device includes a two-way radio for communication among employees. It can also communicate through satellite networks, ideal for remote workers in areas lacking cellphone coverage.
While it is clearly an advantage to have a single gas monitor that can detect many different hazards, multi-gas monitors do have limitations, Douglas says.
First, a worker should always be aware the monitor may not detect everything in the air. It’s up to the employer to make sure workers are provided with the right equipment and training so they know how to use the equipment and are aware of the monitor’s limitations.
Second, where there are many exotic chemicals, such as in an oil refinery, the chemicals can cause cross-interference in certain sensors. In this case, a monitor may misidentify a chemical. For example, a standard feature in four- and five-gas monitors is a carbon monoxide (CO) sensor. However, if hydrogen is present, it can make the carbon monoxide alarm go off.
“And it won’t be carbon monoxide; it will be hydrogen, and hydrogen is extremely flammable and dangerous. So, the worker may see their carbon monoxide detector sensor telling them there’s an alarm condition, but they will not treat it as an urgent, hydrogen alarm,” Douglas says. “That’s where the company needs to understand their hazards, and if they have any potential cross-interferences, they need to educate the worker that just because the CO alarm goes off it doesn’t necessarily mean it is CO; it could be something else. It’s not going to automatically tell you it’s hydrogen. The training can get very sophisticated if your work environment is very sophisticated.”
Linda Johnson is a Toronto-based freelance journalist who has been writing for COS for eight years.
This article originally appeared in the April/May 2019 issue of COS.