What You Should Know About Using Calibration Gases
A poorly calibrated gas detector can put workers at risk. Learn more about calibration gases and how they could save your life.
When you’re working with gases or in confined spaces where the atmosphere may contain harmful gases, having an accurate gas detector is essential. Without it, workers may be at risk of illness and injury without even realizing it. But to do its job properly, the detector must be well calibrated. Gas detectors are meant to save lives, but when they are inaccurate or incorrectly calibrated, they can become a serious risk.
Calibration gases are the unsung heroes of gas detection. But what are they, exactly? How do you use them? What specific things do you need to consider before using them? Before you set off to test your detectors, let's take a closer look at calibration and get some answers to these questions.
What Are Calibration Gases?
Simply put, calibration gases are used to calibrate gas detectors and ensure their proper functioning.
The only way to confirm that a gas detector is accurate is to test it with a known concentration of gas – that is, a calibration gas. By exposing the detector to a confirmed concentration of a particular gas, users can determine whether the sensors respond accurately or provide an erroneous reading. They can also test whether the device alarms are working as they should.
Where Are Calibration Gases Used?
Gas detectors are used in nearly every safety application, which means that calibration gases are also required. Some common applications include:
- Pulp and paper mills
- Petrochemical plants
- Pharmaceutical facilities
- City governments
- Any confined space work
When to Use Calibration Gases
Calibration gases are necessary any time a calibration test or full calibration is being performed. While there is no hard and fast rule as to when a device must be calibrated, OSHA lays out some best practices that should be followed:
- A functional test (also known as a bump test) or full calibration should be performed each day before using direct reading portable gas monitor
- A full calibration must be carried out on any instrument that fails the functional test
- Calibration should be conducted more frequently if environmental conditions could affect device performance (e.g. sensor poisons, high gas concentrations, extreme temperature, mechanical shock or stress) are suspected to be present
If ever in doubt, conduct a full calibration. By exposing the detector to a known concentration calibration gas, you can confirm the accuracy of the reading and the proper functioning of the alarm.
Employers that fail to regularly test and document instrument performance are vulnerable to regulatory fines and the occurrence of serious and preventable workplace accidents.
Calibration Is Only as Accurate as the Test Gas
It goes without saying that the results can be disastrous if calibration is conducted incorrectly or if the gas is not appropriate for the instrument being tested. OSHA recommends using the calibration gases available through the Agency Expendable Supplies Program for the specific instrument you are using. But no matter where your gas comes from, be sure to ask your supplier for a traceable certificate of analysis for every single cylinder you get.
It’s critical to ensure the expiration date marked on the cylinder has not passed. The concentration of a calibration gas only remains stable for a limited time, particularly with reactive gases like hydrogen sulfide and chlorine. For this reason, gas past its expiration date cannot be confirmed accurate and should never be used.
When testing a device with multiple sensors, take care to confirm that you have the proper gas mix. Sometimes, mixes can adversely affect other sensors on the instrument, calling all your test results into question. It’s also a good idea to ask the supplier for a certificate of analysis for every test gas cylinder. You want to be sure that what they say is in the cylinder really is there.
This might seem like a lot of fuss. But when it comes to your test gas, it’s best not to take any chances.
No matter how careful you are, sometimes things get overlooked. And when you’re dealing with potentially harmful gases and the safety of workers, that’s not such a good thing.
Review these helpful reminders to make sure your gas testing is as comprehensive as it can be.
- Always make sure your device is zeroed in fresh air (like an office environment)
- Perform a calibration check each day before the gas detector is used
- Full calibrations should be done at least monthly
- Verify the values the instrument uses to ensure sensor readings match the concentrations listed on the calibration gas cylinder label (the wrong concentration gas can produce inaccurate readings)
- Use the correct regulators and fittings to supply calibration gas to an instrument, as incorrect flows can produce inaccurate readings
If you’re at all uncertain about a step in the calibration process or how to determine whether the gas you’re using is the right one, don’t hesitate to get a second opinion from someone knowledgeable or speak to the instrument's manufacturer.
When it comes to working with gas detectors, calibration can save your life. Be sure to follow all of the best practices when calibrating your devices and never take your calibration gas for granted.
More from AD Safety Network
- When should you consider using custom molded earplugs?
- At what height do falls become deadly?
- Who should be responsible for rescuing fallen workers?
- What kind of training do loading dock workers need?
- How often should I inspect a loading dock?
- How is wind chill calculated?
- What is the difference between occupational safety and process safety?
- Why should rubber insulating gloves be tested?
- What happens if I tie off at the foot level with a personal SRL?
- Why is testing with a NAIL4PET accredited lab important?
- What kind of face protection do I need when using a chainsaw?
- What is the permissible exposure limit (PEL) for silica?
- What is silica and why is it hazardous?
- What is 'Table 1' and why is it so important?
- Video Q&A - What is a safety policy?
- What kind of fire extinguisher is best for your work site?
- How do I choose the right respirator and mask for working with silica?
- Can I wear fall protection equipment over my rainwear or winter gear?
- When do I need a cage ladder?
- What types of gloves protect your hands from hazardous chemicals?
- How come I still got hurt while wearing flame-resistant clothing?
- What dangers do workers face when working outside in the winter?
- How do I win over my most reluctant employees?
- What kinds of jobs should use disposable safety gloves?
- Is it true that safety shouldn't be a top priority?
- When are employers allowed to conduct drug and alcohol tests on their employees?
- How can I get employees more involved in the risk assessment plan?
- What are some of the indirect costs of workplace accidents?
- How often do fire extinguishers need to be inspected?
- What is the best way to store rubber safety gloves?
- How much voltage protection is needed for safety gloves used in electrical work?
- What is the difference between a safety valve and a release valve?
- When do workers have the right to refuse to work?
- What is the most overlooked item when designing Lockout/Tagout (LOTO) procedures?
- What are some of the misconceptions about heat stress and what should we do to address them?
- What tools should I tether when working at heights?
- What types of gas should I watch out for when working in a confined space?
- How do you create a culture of safety in your workplace?
- What is the difference between industrial safety and industrial hygiene?
- Is it important to get PPE assessments by trained professionals?
- What is a fault tree analysis?
- What kind of respirator cartridge should I use?
- What are the safety benefits of a whistleblower program?
- What type of safety record-keeping and recording should we be doing?
- What makes a hi-vis safety vest ANSI compliant?
- Why is it important to have air sampling done to determine my PELs?
- What is the life expectancy of fall protection equipment?
- What are some basic fall protection rules that each of my workers need to understand?
- How much clearance do I need to safely use a Leading Edge SRL?
- What is the difference between an acute hazard and a chronic hazard?
- What’s the difference between a bump test, a calibration check, and a full calibration?
- Is there any legislation regulating lone worker safety I should know about before hiring?
- What kind of fire extinguisher and accessories should be kept on hand on a factory floor?
- What can companies do to reduce their lost time injury frequency rates?
- Video Q&A - What's your safety network like?
- Video Q&A - What are the 3 levels of safety?
- Video Q&A - How do you treat a near miss?
- Does body weight affect falls differently?
- What ages are most affected by falls?
- Why do workers take risks?
- What Is the Difference Between OHSAS 18001 and 18002?
- What is the difference between lost time injury and medical treatment case?
- What is the difference between occupational health and safety and workplace health and safety?
- What is the difference between occupational health and occupational safety?
- What is the difference between a lost time injury and a disabling injury?