13 Aug Atmospheric Testing – JSA

Atmospheric Testing Job Safety Analysis (JSA)

Job / Task

Atmospheric testing and monitoring of confined spaces, permit-required confined spaces, excavations, tanks, vessels, vaults, manholes, process areas, and other locations where oxygen deficiency or enrichment, flammable gases or vapors, or toxic contaminants may be present.

Purpose

This Job Safety Analysis (JSA), also known as a Job Hazard Analysis (JHA), identifies hazards associated with atmospheric testing and establishes controls for selecting, inspecting, function-checking, calibrating, using, and interpreting direct-reading gas-monitoring instruments.

Personnel Qualifications

Atmospheric testing shall be performed by trained personnel who understand the monitoring instrument, anticipated contaminants, alarm settings, sampling limitations, required testing sequence, acceptable atmospheric conditions, and actions required when hazardous conditions are detected.

Employees performing atmospheric testing shall:

• Be trained in the specific monitor and accessories used.
• Understand the hazards and contaminants that may reasonably be present.
• Know the instrument’s sensors, detection limitations, alarm indications, and manufacturer requirements.
• Perform required pre-use inspections, functional checks, and calibrations.
• Use remote sampling methods when testing a potentially hazardous space before entry.
• Understand that atmospheric conditions can vary by location and elevation and can change during work.
• Immediately communicate hazardous readings, alarms, instrument failures, or changing conditions to affected personnel.

Required PPE

PPE shall be based on the location, task, and anticipated atmospheric or physical hazards and may include:

• Hard hat.
• Safety glasses with side protection or chemical goggles where appropriate.
• Safety footwear.
• Work gloves or chemical-resistant gloves appropriate to the exposure.
• High-visibility apparel where exposed to traffic or mobile equipment.
• Hearing protection where required.
• Fall-protection equipment where required.
• Respiratory protection when required under the respiratory-protection program.
• Chemical-resistant or other protective clothing when required.
• Additional task-specific PPE identified by the hazard assessment.

JSA – Job Steps, Hazards, and Controls

Step 1 – Identify the Area and Testing Objective

Potential Hazards

• Unknown atmospheric hazards.
• Testing for the wrong contaminants.

Required Controls

• Determine why atmospheric testing is required and identify the space or work area to be tested.
• Review the work scope, process history, SDSs, prior monitoring results, permits, and known or reasonably anticipated contaminants.
• Determine whether testing is for pre-entry evaluation, continuous monitoring, leak detection, hot work, emergency response, or another purpose.
• Do not assume a standard four-gas monitor detects every possible hazardous contaminant.

Step 2 – Evaluate Potential Atmospheric Hazards

Potential Hazards

• Oxygen deficiency or enrichment.
• Flammable atmosphere.
• Toxic exposure.

Required Controls

• Identify sources that could consume or displace oxygen.
• Identify combustible gases, vapors, or mists that may be present.
• Identify toxic gases or vapors requiring specific sensors or sampling methods.
• Consider residues, decomposition, cleaning products, welding, coatings, engines, nearby processes, and connected piping.
• Select monitoring equipment capable of detecting the hazards identified.

Step 3 – Review Acceptable Entry / Work Conditions

Potential Hazards

• Misinterpretation of readings.
• Exposure to unsafe atmosphere.

Required Controls

• Know the acceptable atmospheric limits established by the applicable permit, program, procedure, or exposure criteria.
• Verify alarm settings are appropriate for the intended use and have not been improperly changed.
• Understand that monitor alarms are warning thresholds and do not replace applicable occupational exposure limits or task-specific evaluations.
• Establish evacuation or stop-work criteria before testing begins.

Step 4 – Select the Appropriate Gas Monitor

Potential Hazards

• Undetected contaminant.
• Incorrect sensor range.
• Instrument incompatibility.

Required Controls

• Select an instrument with sensors appropriate for oxygen, combustible gases or vapors, and identified toxic contaminants.
• Verify sensor ranges and resolution are suitable for the expected concentrations.
• Use intrinsically safe or appropriately approved equipment where required by the environment.
• Use additional or specialized instruments when contaminants are not detected by the standard monitor.
• Follow manufacturer instructions for instrument selection and use.

Step 5 – Inspect the Monitor

Potential Hazards

• Instrument failure.
• False or unreliable readings.

Required Controls

• Inspect the monitor, housing, display, buttons, alarms, battery, sensors, filters, tubing, probes, and accessories before use.
• Verify the battery has sufficient charge for the anticipated monitoring period.
• Check for blocked or contaminated sensor openings.
• Inspect sampling tubing for cracks, contamination, kinks, or moisture.
• Remove defective equipment from service.

Step 6 – Verify Calibration Status

Potential Hazards

• Inaccurate readings.
• Failure to alarm.

Required Controls

• Verify calibration is current according to manufacturer instructions and the atmospheric-monitoring program.
• Use only the correct calibration gas and regulator specified for the instrument.
• Do not use expired or improperly stored calibration gas.
• Calibrate the instrument when required by the manufacturer, program, failed functional check, sensor replacement, or other condition affecting accuracy.
• Document calibration when required.

Step 7 – Perform a Functional / Bump Test

Potential Hazards

• Sensor failure.
• Alarm failure.
• False sense of security.

Required Controls

• Perform the required pre-use functional or bump test according to manufacturer instructions and company procedures.
• Verify each sensor responds to the test gas.
• Verify audible, visual, and vibrating alarms function as applicable.
• Do not use a monitor that fails the functional test.
• Calibrate or remove the monitor from service if the test results are unacceptable.

Step 8 – Zero / Fresh-Air Set the Instrument

Potential Hazards

• Incorrect baseline.
• False readings.

Required Controls

• Perform zeroing or fresh-air setup only in an atmosphere known to be clean and appropriate for the instrument.
• Do not zero a monitor in an area suspected of containing contaminants.
• Follow manufacturer procedures for automatic or manual zeroing.
• Allow the instrument to complete its startup sequence before use.
• Investigate unexpected baseline readings.

Step 9 – Establish a Safe Testing Position

Potential Hazards

• Exposure before atmosphere is evaluated.
• Fall into opening.
• Traffic or equipment strike.

Required Controls

• Remain outside a potentially hazardous confined space during pre-entry testing.
• Guard or barricade openings as required.
• Position the tester away from traffic, equipment movement, exhaust, and other unrelated hazards.
• Use remote sampling equipment when the atmosphere cannot be safely tested directly.
• Do not place the head or upper body into a space merely to obtain a reading.

Step 10 – Test in the Proper Sequence

Potential Hazards

• Fire or explosion.
• Toxic exposure.
• Incorrect combustible-gas reading.

Required Controls

• Test oxygen concentration first, then combustible gases and vapors, followed by toxic contaminants unless the instrument manufacturer or specific procedure requires another validated method.
• Recognize that some combustible-gas sensors may provide unreliable readings in oxygen-deficient atmospheres.
• Allow adequate response time for each sensor.
• Do not proceed with entry when readings are outside acceptable conditions.

Step 11 – Test at Multiple Levels and Locations

Potential Hazards

• Missed stratified gases.
• Localized hazardous atmosphere.

Required Controls

• Sample the top, middle, and bottom of the space where atmospheric stratification may occur.
• Test remote corners, dead spaces, sumps, low points, high points, and work locations as applicable.
• Consider vapor density and the physical characteristics of anticipated contaminants.
• Move the probe slowly enough to allow the instrument to respond.
• Do not rely on a single reading at the opening.

Step 12 – Use a Sampling Pump and Tubing

Potential Hazards

• Delayed readings.
• Blocked sample line.
• Contaminated tubing.

Required Controls

• Verify pump operation before use.
• Account for tubing length and instrument response time before accepting a reading.
• Use tubing compatible with the contaminants being sampled.
• Keep tubing free of kinks, liquid, dirt, and obstructions.
• Allow sufficient purge time when moving between sampling locations.

Step 13 – Evaluate Oxygen Concentration

Potential Hazards

• Asphyxiation.
• Increased fire hazard.

Required Controls

• Compare oxygen readings with the acceptable conditions established for the work.
• Treat oxygen-deficient or oxygen-enriched readings as hazardous conditions requiring evaluation and control.
• Do not enter or continue work when oxygen is outside the permitted range unless a specifically authorized procedure and appropriate respiratory protection apply.
• Investigate the source of abnormal oxygen readings.

Step 14 – Evaluate Combustible Gas / Vapor Readings

Potential Hazards

• Fire.
• Explosion.
• Burns.

Required Controls

• Read combustible concentrations as the instrument is designed to display them, commonly as a percentage of the lower explosive limit.
• Follow permit, hot-work, or site-specific limits for acceptable combustible concentrations.
• Eliminate ignition sources and evacuate or restrict access when hazardous readings are detected.
• Do not assume a zero reading proves that all flammable contaminants are absent if the sensor is not appropriate for the material.
• Reassess conditions after ventilation or other controls are applied.

Step 15 – Evaluate Toxic Gas Readings

Potential Hazards

• Poisoning.
• Respiratory injury.
• Delayed health effects.

Required Controls

• Compare readings with applicable entry criteria, alarm settings, and occupational exposure limits.
• Identify whether short-term, ceiling, or time-weighted exposure criteria are relevant to the task.
• Use sensors specifically capable of detecting the anticipated toxic gas.
• Do not ignore low-level readings when the contaminant is highly toxic or may accumulate during work.
• Implement ventilation, isolation, respiratory protection, or evacuation as required.

Step 16 – Record Pre-Entry Test Results

Potential Hazards

• Loss of hazard information.
• Unauthorized entry.

Required Controls

• Document required readings on the confined-space permit, monitoring log, or other required record.
• Record the time of testing and the identity or initials of the tester when required.
• Record oxygen, combustible, and toxic readings as applicable.
• Document unusual conditions or additional contaminants tested.
• Provide results to the entry supervisor and affected entrants.

Step 17 – Establish Continuous or Periodic Monitoring

Potential Hazards

• Atmospheric conditions change after entry.
• Delayed detection.

Required Controls

• Determine monitoring frequency based on the hazards, work activity, permit, and potential for changing conditions.
• Use continuous monitoring when required or when conditions can change rapidly.
• Position personal or area monitors where they will represent entrant breathing zones and work locations as appropriate.
• Maintain monitor visibility or alarm audibility.
• Do not discontinue required monitoring because initial readings were acceptable.

Step 18 – Monitor During Ventilation

Potential Hazards

• False assumption that ventilation is effective.
• Recontamination.

Required Controls

• Verify ventilation actually maintains acceptable atmospheric conditions.
• Test areas where entrants are working, not only near the ventilation discharge.
• Monitor for contaminants introduced by work processes.
• Keep ventilation intakes away from vehicle exhaust, generators, or contaminated air.
• Stop entry if ventilation fails and atmospheric safety cannot be assured.

Step 19 – Monitor During Hot Work

Potential Hazards

• Rapid atmospheric change.
• Fire or explosion.
• Fume exposure.

Required Controls

• Conduct atmospheric monitoring at the frequency required by the hot-work and confined-space procedures.
• Monitor for combustible gases or vapors and relevant toxic contaminants.
• Maintain effective ventilation.
• Stop hot work and evacuate when readings exceed acceptable conditions or alarms activate.
• Reevaluate the atmosphere before work resumes.

Step 20 – Monitor for Carbon Monoxide / Combustion Products

Potential Hazards

• Carbon monoxide poisoning.
• Oxygen depletion.

Required Controls

• Keep engines, generators, heaters, and other combustion sources away from confined spaces and ventilation intakes whenever possible.
• Use appropriate sensors when combustion products may enter the work area.
• Monitor continuously or at an appropriate frequency when conditions warrant.
• Investigate increasing readings immediately.
• Stop work and evacuate when acceptable conditions cannot be maintained.

Step 21 – Respond to an Alarm

Potential Hazards

• Toxic exposure.
• Asphyxiation.
• Fire or explosion.

Required Controls

• Treat every alarm as a potential hazardous condition.
• Affected personnel shall leave the hazardous area or confined space as required by the applicable procedure.
• Do not silence, reset, or disregard an alarm merely to continue work.
• Identify and correct the cause before reentry or work resumes.
• Retest and obtain required authorization before resuming entry.

Step 22 – Respond to Unexpected or Erratic Readings

Potential Hazards

• Undetected hazard.
• Instrument malfunction.

Required Controls

• Stop work when readings are inconsistent, rapidly changing, or unreasonable.
• Move to a safe location before troubleshooting the instrument.
• Check for sensor saturation, contamination, blocked tubing, depleted battery, or calibration problems.
• Use another verified instrument when necessary.
• Do not assume an unexpected reading is an instrument error until the atmosphere has been shown to be safe.

Step 23 – Respond to Monitor Failure

Potential Hazards

• Loss of atmospheric protection.
• Undetected exposure.

Required Controls

• Stop entry or work requiring atmospheric monitoring when the monitor fails.
• Evacuate entrants if required monitoring cannot be maintained.
• Replace the instrument with a properly inspected and function-tested monitor.
• Do not continue relying on a monitor with a failed sensor, alarm, pump, battery, or display.
• Document or tag defective equipment as required.

Step 24 – Re-Test After Work Interruption

Potential Hazards

• Atmosphere changed during shutdown.
• Hazardous reentry.

Required Controls

• Reevaluate the atmosphere after breaks, evacuations, ventilation interruptions, process changes, or other events that could affect conditions.
• Repeat pre-entry testing when required by the permit or procedure.
• Verify isolation and ventilation remain effective.
• Do not assume previous readings remain valid.
• Document new readings when required.

Step 25 – Maintain Personal Monitors

Potential Hazards

• Monitor positioned incorrectly.
• Alarm not detected.

Required Controls

• Wear personal monitors in the location specified by the manufacturer and program, generally within the breathing zone when monitoring inhalation hazards.
• Keep sensor openings unobstructed.
• Do not cover the monitor with clothing or PPE in a way that interferes with sampling or alarms.
• Protect the instrument from water, impact, contamination, and extreme conditions beyond its rating.
• Check the display and status periodically.

Step 26 – Prevent Sensor Interference / Cross-Sensitivity

Potential Hazards

• False positive or false negative readings.

Required Controls

• Understand known sensor limitations and cross-sensitivities relevant to the contaminants present.
• Avoid exposing sensors to substances known to poison or inhibit them when possible.
• Recheck calibration or sensor performance after suspected damaging exposure.
• Use alternate detection methods when the selected sensor cannot reliably distinguish or measure the hazard.
• Consult manufacturer information when unusual readings occur.

Step 27 – Complete Post-Use Inspection

Potential Hazards

• Damaged equipment returned to service.
• Contamination.

Required Controls

• Inspect the monitor after use.
• Clean the instrument and accessories using manufacturer-approved methods.
• Do not use solvents or cleaners that can damage or poison sensors.
• Check tubing, filters, probes, and pumps for contamination or moisture.
• Report damage or abnormal operation.

Step 28 – Charge and Store the Monitor

Potential Hazards

• Dead battery.
• Sensor degradation.
• Calibration problems.

Required Controls

• Charge or replace batteries according to manufacturer instructions.
• Store instruments in a clean, dry, temperature-controlled location suitable for the sensors.
• Protect monitors from chemicals, silicone vapors, solvents, and other contaminants that may affect sensor performance.
• Store calibration gas correctly and monitor expiration dates.
• Maintain equipment so it is ready for the next use.

Step 29 – Maintain Monitoring Records

Potential Hazards

• Missing documentation.
• Failure to identify recurring hazards.

Required Controls

• Retain calibration, functional-test, permit, and atmospheric-monitoring records as required by the applicable program.
• Document instrument identification when required.
• Report repeated alarms, unusual readings, or sensor failures for evaluation.
• Use monitoring history to improve future hazard assessments and entry planning.

General Safe Work Requirements

• Atmospheric testing shall be performed by trained personnel using instruments suitable for the hazards being evaluated.
• Monitoring instruments shall be inspected and function-tested before use and calibrated according to manufacturer instructions and the applicable program.
• Pre-entry testing shall be performed from outside the confined space whenever feasible.
• Atmospheric testing shall account for stratification and localized hazards by sampling appropriate levels and locations.
• Testing shall evaluate oxygen, combustible gases or vapors, and toxic contaminants applicable to the space and work.
• A standard multi-gas monitor shall not be considered capable of detecting contaminants for which it has no appropriate sensor.
• Adequate instrument response and tubing transport time shall be allowed before readings are accepted.
• Required atmospheric monitoring shall continue for the duration of the work or entry at the frequency necessary to detect changing conditions.
• Personnel shall immediately respond to monitor alarms and shall not disregard, disable, or silence alarms merely to continue work.
• Entry or work shall stop if atmospheric conditions exceed established limits or if required monitoring equipment fails.
• Atmospheric conditions shall be reevaluated after ventilation failure, work interruption, process changes, evacuation, or other events that may affect the atmosphere.
• Monitoring results shall be documented when required by the permit, procedure, or program.
• Defective or unreliable instruments shall be removed from service.

Training

Employees performing atmospheric testing shall receive training before independently using monitoring equipment. Training shall address atmospheric hazards, oxygen deficiency and enrichment, combustible and toxic contaminants, monitor selection, sensor limitations, alarm settings, inspection, functional testing, calibration, fresh-air zeroing, remote sampling, testing sequence, stratification, sampling-pump response time, interpretation of readings, continuous monitoring, documentation, alarm response, instrument failure, maintenance, and storage. Retraining shall be provided when equipment changes, procedures change, or employee knowledge or performance indicates a deficiency.

References

• OSHA 29 CFR 1910.146 – Permit-Required Confined Spaces, where applicable.
• OSHA 29 CFR 1926 Subpart AA – Confined Spaces in Construction.
• OSHA 29 CFR 1926.1203 – General Requirements.
• OSHA 29 CFR 1926.1204 – Permit-Required Confined Space Program.
• Applicable respiratory-protection, hot-work, confined-space, and emergency-response procedures.
• Atmospheric-monitor manufacturer instructions and sensor-specific technical information.
• Applicable site and client requirements.