It’s the mantra of every industrial hygienist in every industry: use every means possible to keep employees, contractors and the public safe. It’s a big responsibility, and it’s one these professionals take seriously.
While these safety experts ply their skills across diverse industries – from pharmaceuticals, paints and plastics to food processing, chemicals and power plants – the stark reality of what could go wrong always is foremost in the minds of safety managers and industrial hygienists in the oil and gas refinery industry.
Just 3 years ago, the catastrophic event that refinery safety professionals fear most happened at a Texas refinery. A hydrocarbon-vapor explosion resulted in 15 deaths and more than 180 injuries, mostly contract employees onsite that day during a plant turnaround project. That incident still fuels countless safety discussions today for industrial hygienists.
Even though the oil and gas industry is mature, it continues to experience rapid growth, and new monitoring policies and solutions are being sought and deployed in an effort to keep human safety the top priority in these risk-intensive environments. Sharing industry best practices is one way professionals stay abreast of safety concerns and keeps many companies ahead of OSHA mandates.
Perhaps even more effective is the growing utilization of computer-based solutions that allow industrial hygienists to extract valuable information to better detect potential hot spots, manage alarms remotely and keep detailed exposure logs. And with the advent of new wireless solutions, industrial hygienists can increase safety protocols while reducing costly worker downtime. And it doesn’t stop with today’s latest technology. Many industrial hygienists are looking to instrument manufacturers to further enhance current solutions and develop new ones.
Applications for toxic gas-detection monitoring in the petrochemical field fall into one of three categories:
1) Worker or personal monitors, which typically are worn or carried by individuals to alert them when chemical gas exposures occur.
2) Integrating monitors, which are worn by workers to collect time-weighted and full-shift exposure data and typically are operated by industrial hygienists.
3) Wireless area or location-based monitors that typically are used to ensure safe entry into confined spaces or monitor emissions at a facility fence line and are used as backup when fixed monitors lose power.
OSHA mandates exposure limits, called permissible exposure levels (PELs), expressed as time-weighted averages (TWAs) or short-term exposure limits (STELs). Most PEL limits are set for an 8-hour period while STELs are set as 15-minute time-weighted averages. Industrial hygienists strive to eliminate hazards by substituting less hazardous chemicals whenever possible or by implementing engineering controls to ensure human safety.
Still, additional safeguards are utilized, including having employees who enter a potentially hazardous area wear appropriate personal protective equipment (PPE), including dermal and respiratory protection. Industrial hygienists also may implement safety protocols requiring the use of toxic gas-detectors, which are bump tested at regular intervals and calibrated to ensure the devices function correctly.
Industry Best Practices
It is common for industrial hygienists to compare notes and share approaches not only with their own facilities around the world but also with competitors. Many industrial hygienists are members of the American Industrial Hygiene Association (AIHA) and the American Conference of Governmental Industrial Hygienists (ACGIH), both national organizations that promote occupational health. The ACGIH establishes threshold limit values (TLVs) which are industry-wide guidelines for exposure limits on more than 700 chemical substances and physical agents, and more than 50 biological exposure indices (BEI).
“Companies today are global so they deal with a myriad of regulations from around the world,” says Laurie Cullom, an 8-year industrial hygiene veteran who is one of the safety managers at the ConocoPhillips refinery in Rodeo, Calif. “We often look at other countries to see what is the best practice for keeping exposures down. The global nature of companies today helps because we can see what’s happening and learn from what’s going on in other parts of the world.”
For many industrial hygienists, one of the leading best practices today is the increased deployment of multi-sensor personal gas-detection monitors with photoionization detectors (PIDs), particularly due to the risk of several types of gas in refinery environments – including hydrogen sulfide (H2S), sulfur dioxide (SO2), carbon monoxide (CO) and oxygen (O2) for oxygen-enriched or oxygen-deficient environments. PIDs effectively monitor hydrocarbon vapors, and specialized PIDs monitor benzene levels in addition to other volatile organic compounds (VOCs) and lower explosive limits (LELs). The first multi-sensor gas monitors to include PIDs were introduced by the San Jose, Calif.-based manufacturer RAE Systems in 1996.
Many industrial hygienists continue to require single-gas monitors for anyone going into the refinery and increasingly utilize more multi-sensor personal gas-detection monitors. At ConocoPhillips, the four-gas personal detection monitor with PID advances worker health issues in addition to safety concerns.
“Having a four-gas meter with a PID has really done a lot to increase our safety,” says Cullom. “Now we have a device that will alert workers to immediate dangers, such as flammability issues or toxic levels of CO, H2S or issues with oxygen, but also gives them a tool to determine health hazards, such as benzene presence, with just a look at the VOC reading. Now all workers are utilizing a tool that industrial hygienists have been using for years. It really has been a big step forward in advancing both worker health and safety in our facilities.”
Lowering Exposure Limits
Lowering exposure limits for benzene is another area where oil refineries are aggressively implementing best practices. Benzene is a colorless liquid with a sweet odor that is volatile and highly flammable. Derived mostly from petroleum sources, it is one of the most commonly produced chemicals in the United States. While it is prevalent in many industries, including in manufacturing of rubber, dyes, drugs, explosives and other products, it is extremely common in oil refineries. It is a known carcinogen and a suspected toxicant to many internal human systems, including cardiovascular and respiratory systems.
OSHA responded to the health threats posed by benzene exposure by setting permissible exposure limits (PEL) at 1 part-per-million (ppm) over an 8-hour TWA period and a STEL of 5 ppm. OSHA also established regulations on monitoring and measuring benzene exposure in its standards – codified in Title 29 CFR Part 1910.1028 – which include using devices such as personal and portable detection monitors.
As part of an industry best practice, most oil refineries, as well as companies in other industries, have adopted exposure limits that are more stringent than those set by OSHA. This is driven in part through TLVs set forth by ACGIH. That organization recommends TWAs of 0.5 ppm and a STEL of 2.5 ppm. Stricter yet are the TWA recommendations established by the National Institute of Occupational Safety and Health (NIOSH). It suggests a TWA of 0.1 ppm and a STEL of just 1 ppm.
“Typically, as the science of toxic exposure improves, exposure limits become more aggressive,” says Cullom. “As industrial hygienists, we try to be proactive in lowering exposure limits to safe and sane levels.”
Other compounds now are under the watchful eyes of industrial hygienists, including sulfur dioxide (SO2) and hydrogen sulfide (H2S), two of the most prevalent toxic gases at refineries.
New Directions in Gas Detection
Increasingly, industrial hygienists at oil refineries are utilizing more computer-based solutions to gather additional exposure information about plant sites or specific areas within the plants, and to manage, store and retrieve gas-detection monitoring data. While gas-monitoring solutions have been around for decades, applications that allow data analysis of monitoring data have only recently become common tools for industrial hygienists. Air-quality monitoring equipment capable of uploading monitoring information to centralized corporate databases now allow safety and health professionals to access data over a secure internet server and view data real time from any computer with access to an internet connection.
The AreaRAE from RAE Systems is one example of a system that incorporates a built-in radio-frequency (RF) modem to transmit data wirelessly. This allows industrial hygienists to access the system remotely from any location with Internet access. For example, if an after-hours problem arises at a refinery plant, an industrial hygienist can access the network from home and help troubleshoot the situation immediately.
Additionally, continuous gas-detection monitors can be used to collect data, such as contaminant-concentration information, in specific areas around a plant. The data then can be collected and stored on a local-area network (LAN) and uploaded to a secure Web server.
Other monitors are ideal for sampling air quality to collect time-weighted and full-shift data for a wide range of toxic gases. Industrial hygienists often will equip a worker with a portable monitor, placing an air sampling tube over the worker’s shoulder to effectively monitor worker breathing zones to assess potential exposures. This kind of personal exposure data is useful and statistical analysis of that data can help industrial hygienists in the decision-making process. By using data analysis tools, industrial hygienists can look at the probabilities of exceeding certain exposure levels in the future based on current measurements.
Wireless Toxic Gas Monitors
Cost reduction is another key benefit to implementing wireless-based monitoring systems in addition to backstopping other gas-detection monitoring approaches. Continuous monitoring strategies increasingly are being deployed at oil refineries around the globe during extensive and expensive turnarounds and other maintenance activities. Wireless gas monitors often are used for confined-space entry during these maintenance activities.
Companies initially balked at the higher price tag of wireless systems, but are finding the systems quickly pay for themselves. According to manufacturers, wireless solutions typically have a return-on-investment within the first deployment.
Plant turnarounds require shutting down a large hydrocarbon-processing unit for periodic maintenance, retrofits and upgrades. Many refining units require maintenance shutdowns every few years.
These shutdowns are necessary to ensure worn parts, pumps and pressure valves are maintained properly to keep them working reliably and at peak efficiency. Turnarounds also greatly reduce the probability of unscheduled failures or shutdowns, which can be extremely costly to petroleum manufacturers. In addition, plant turnarounds also reduce the chances of catastrophic accidents.
Wireless monitors that provide real time, continuous monitoring are typically used to monitor confined spaces, such as pressure vessels, storage tanks or valve-system areas. Continuous monitors evaluate the atmosphere inside confined spaces and can save a significant amount of time during the course of the turnaround project. For instance, if an alarm goes off in an adjacent area to the turnaround project, safety policies dictate that the turnaround vessel be cleared. Once the nearby alarm is addressed, the turnaround vessel – which can be up to 20-stories high – needs to be recertified as safe to enter.
By using continuous monitoring in confined spaces, industrial hygienists may not have to walk through the entire unit or piece of equipment if the monitors show it was safe through the entire incident. That means workers back can get back to work sooner, which can save significant time and money.
Continuous monitors are now being deployed in other ways as well to enhance worker safety throughout plants. These wireless systems also can monitor potential problem areas, such as remote underground storage tanks, to ensure the area is safe for workers to enter. In addition, many oil refineries have adopted wireless systems as fence line monitors to support “good neighbor” programs and to monitor remote areas where fixed wires and electricity are not installed. Continuous fence monitoring provides real-time information about gases crossing the property line at ground level, which can be important information if an unusual event occurs.
Looking to the future, industrial hygienists seek more data management tools, especially those with easy-to-use interfaces and improved capabilities, such as flexible reporting configurations. Trends indicate further implementation of wireless monitors and increased use of continuous monitoring systems, which may help reduce the use of the personal gas-detection devices. At the same time, manufacturers are enhancing wireless monitoring systems to improve operational distances, reduce interference and extend operational time in the field.
Working together, manufacturers and safety professionals are making oil and gas refineries a safer place to work today – and in the future.
Bob Durstenfeld is a communications director for RAE Systems Inc. (http://www.raesystems .com), based in San Jose, Calif.