Authorized Gas Tester (AGT) study plan

Explain how molecular weight and relative vapour density determine where a gas accumulates in a confined space, and predict the layer for at least six named substances.

Distinguish flash point, auto-ignition temperature, lower and upper flammable limits, and stoichiometric concentration, and state why the flammable range widens as oxygen content rises.

Describe how temperature, pressure and air movement change the volume-percent reading of a gas and calculate a simple pressure correction.

Classify oxygen, nitrogen, methane, hydrogen sulphide, carbon monoxide and carbon dioxide by toxicity, flammability and simple asphyxiation mode.

Explain the physiological effects of oxygen at 19.5%, 18%, 16%, 12% and below 10% and state the oxygen concentration at which each effect begins.

Describe how oxygen enrichment raises combustion rate and lowers the ignition energy needed, and identify at least three oxygen-enriched atmospheres risks in hot work.

Explain inerting and purging: how nitrogen purging changes oxygen and flammable gas readings, and why entry into an inerted space is prohibited.

Calculate the effect on oxygen concentration of adding a known volume of nitrogen or carbon dioxide to a sealed space.

Outline the employer and employee duties that apply to confined space entry, hot work and gas testing in the jurisdiction in which you will work, citing the relevant instrument by name.

Define the roles of the authorized gas tester, entry supervisor, standby person and entrant, and state who may authorize entry and who may suspend it.

Explain the purpose and required content of a permit to work and a confined space entry certificate, including validity period, suspension and cancellation.

Apply the hierarchy of control to a sample confined space task and justify each control chosen.

Distinguish a risk assessment from a safe system of work and describe how gas test results feed into both.

Compare catalytic bead, infrared, electrochemical and photoionization detection principles, and state one substance each suits and one it cannot measure.

Explain cross-sensitivity, poisoning and inhibition of catalytic and electrochemical sensors, naming at least three interfering substances.

Describe the limitations of colorimetric detector tubes, including stroke count, temperature, humidity and tube shelf life.

Select the correct instrument and sensor combination for pre-entry testing of a sewer manhole, a fuel tank and a confined space with solvent residue.

Explain why oxygen must be tested before flammable gas and why readings must be taken at multiple levels.

Distinguish a calibration check, a functional bump test and a full calibration, and state when each is required.

Perform and document a bump test and a fresh-air zero on a multi-gas monitor, recording pass or fail against the manufacturer specification.

Explain the role of certified span gas, its concentration, expiry and traceability, and identify common calibration errors.

Describe the daily and pre-use checks that must precede any entry test, including battery, pump flow, filter and alarm function.

State the actions required when an instrument fails a bump test or drifts beyond tolerance.

Sequence a pre-entry test: fresh-air zero, oxygen, flammable gas, toxic gas, then stratified sampling at top, middle and bottom.

Explain when continuous monitoring is mandatory and how often manual re-testing should occur during an entry.

Define the acceptance criteria for entry and the actions to take when a reading approaches or crosses an alarm set point.

Describe purge and ventilation strategy, including how to confirm ventilation has been effective before re-testing.

Explain sample-line effects such as length, lag time and absorption, and how to allow for them.

State the flammable gas acceptance criteria for hot work and explain why a zero reading alone may be insufficient near low flash point liquids.

Explain hot work in a zone where flammable vapour may be released, and how continuous monitoring and a fire watch are arranged.

Describe the risk of flammable gas entering drains, ducts and voids adjacent to hot work and how to test them.

Explain how hot work permits interact with confined space permits when both apply to the same task.

Design a record sheet that captures instrument details, calibration status, test points, readings, times, tester identity and permit reference.

Explain the communication chain during an entry, including alarm raising, evacuation and rescue initiation.

Describe the elements of a confined space rescue plan and why non-entry rescue is preferred, and state why rescuers must not enter without protection.

Apply a full scenario from first gas test to permit close-out, justifying each decision against the earlier domains.

Identify three common causes of gas testing failure and the control that prevents each.