Useful Industrial Hygiene Tools for Your Lab
How familiar are you with the many IH tools available?
Jonathan Klane, M.S.Ed., CIH, CSP, CHMM, CIT, is senior safety editor for Lab Manager. His EHS and risk career spans more than three decades in various roles as a...
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Imagine any of these scenarios occurred at your lab. Staff are concerned about:
- Offensive odors like rotten eggs
- Exposures to neurotoxic solvents
- Particles and air cleanliness
- Noise from equipment
- How well their respirator fits
Each situation requires a response but with widely different industrial hygiene (IH) sensing tools or meters.
Industrial hygienists use a wide range of sensor technologies—there is no single “magic wand.” There are diverse types of meters or tools available for gases, solvents, noise, radiation, etc. These are typically available to buy, rent, borrow, and are used by internal industrial hygienists and consultants. While they can’t all be covered, here’s an overview of the major tools available by sensor need and IH problem:
Gas sensing:
Gases are ubiquitous in labs, and sensors indicate what gases or vapors are in the air in real time. Gas sensors come in two main flavors—fixed and portable. Fixed sensors are used in gas cabinets and on walls. They measure the gases in that area or space. Portable meters are handy to indicate gas levels in different parts of the space (e.g., near equipment, by drains, or at different heights).
Multi-gas meters have oxygen, combustible gases, and toxic gas sensors (like carbon monoxide and hydrogen sulfide) and are commonly available. Photoionization detectors (PIDs) can be part of a gas meter or as standalone types to sniff for a wide variety of volatile organic compounds (VOCs). PIDs are quantitative (QN) but not entirely qualitative (QL). They indicate total VOCs in ppm, but not the specific chemicals.
A PID can be paired with indicator tubes as a helpful snapshot in real time. Indicator tubes are both QL and QN—they show how much and which type of gas or vapor via color changes to the media in the glass tube (e.g., 100 ppm of acetone versus 10 ppm of ethanol).
Indoor air quality:
We might tolerate some odors in the lab. But in common areas and offices, we expect clean, odor-free air. Indoor air quality (IAQ) concerns or complaints are common around labs.
IAQ meters for general air screening usually detect at least oxygen and carbon dioxide. Oxygen level is obvious to check, but CO2 is a better indicator of ventilation and circulation. They often also indicate temperature and humidity as comfort factors.
IH tools are many, diverse, complex, and a challenge to know what's needed.
Another simple tool is called smoke testing. It’s not actually smoke, it’s a visible aerosolized vapor (often glycol) to visualize air movement. There are also many types of ventilation meters for air flow measurements that help assess stagnant air pockets.
Heat stress:
How hot is too hot? What about the heat index? How am I doing in this heat and humidity? These are all answerable via temperature-related sensors. There are personal meters that measure body heat along with wearable technology with biometrics.
Instead, it can help to measure heat within an area using a WBGT, or wet bulb globe thermometer. It integrates and combines three factors: wet bulb cooling from convective heat loss, globe temperature from radiant heat, and dry bulb for the regular temperature.
Hoods:
There are various factors affecting fume hood effectiveness. Anemometers (e.g., hot wire type) are used to measure face velocities—while important, it’s only a single factor that’s not solidly linked to effective containment. At the sash, it measures air speed as compared to a standard (often 80-120 feet per minute). A more useful indicator that the hood is capturing emissions is a laser light indicator for hood containment at the sash that can also show conditions affecting air flow.
Noise and sound:
Lab equipment can produce noise that’s distracting, irritating, or harmful to hearing. Sound level meters measure noise sources and exposures at any moment and answer, “Is it too loud here? Is that why we didn’t evacuate despite the fire alarm sounding?”
Dosimeters are worn and accumulate noise data over the day to measure the time-weighted average compared to exposure limits (legally mandated or advisory). They answer, “What’s my total daylong exposure compared to exposure limits?”
Vibration:
Vibration meters are available for assessing both workers and sensitive equipment. Daily exposure can cause conditions such as vibration white finger or hand-arm vibration syndrome. Buildings, equipment, outdoor traffic, etc., can all cause lab vibrations transmitted to analytical instruments that interfere with measurement accuracy.
Particles:
Particles are in our air and settle on horizontal surfaces. A particle counter can be used for air cleanliness in any space or in a cleanroom. It answers, “Is our air safe to breathe and clean enough to suit our research?”
How hot is too hot? What about heat index? How am I doing in this heat and humidity? These are all answerable via temperature-related sensors.
They are real-time screening tools that one can use to walk around and find sources of particle generation. In an example, one was used to find vehicle emissions traveling through unsealed wiring conduit from a garage into offices. They’re used for both monitoring health concerns and product integrity.
Lead dust or fumes don’t evaporate—the solid dust settles on surfaces and gets on hands. Surface wipes are a handy tool to detect the presence and amount of specific contaminants like metals. This would address concerns such as, “How much neurotoxic lead is settling on my work surface or getting on my hands from soldering? Could I be transferring it to my family?”
Radiation detection:
Ionizing radiation requires screening to assess human health exposures. Radiation meters are used for screening in real time. They can be used to address concerns by measuring x-ray levels in an adjacent space, for example. Geiger-Mueller and liquid scintillation counters are two common tools.
For personal exposure to individuals, dosimeters and badges are necessary to measure an individual’s total exposure over time. Rings and clip-on badges are helpful options depending on the context.
Air pumps, etc.:
Despite all these cool tools, sometimes air samples are collected and sent out for analysis. Air pumps and sample media help assess exposures compared with OSHA permissible exposure limits or other established limits. They help answer, “Are we over or under the legal exposure limit(s)?”
Personal pumps and area pumps with sampling media and calibrators are needed for any air sampling—chemical, fibers, dusts, or microbiological. If we need to know what unknown VOCs might be present, we can use Summa cans to collect air, which are then analyzed for a large suite of analytes.
Respirator fit testing:
Tight-fitting respirators work only if they fit properly—“Does this respirator really protect me?” To answer this, we can use QL agents like banana oil, irritant smoke, or a bitter compound to provoke a reaction by the wearer. Or we might use a QN fit testing machine that measures the difference between inside and outside the respirator (using particles or pressure) to assess fit.
Labs create various air quality challenges with problematic situations. IH tools are many, diverse, complex, and a challenge to know what’s needed. It’s best practice to be familiar with what might be needed. It’s important to be able to discuss them with an industrial hygienist and staff. If your staff report any of these scenarios, you’ll be prepared to successfully, and confidently, manage them. If all else fails, follow the advice of an electrical engineering researcher who innovates sensors—get a dog. Their nose and sense of smell is better than many of the meters we rely upon—and dogs are much more fun!