Purpose

The Authorised Gas Tester’s role is critical in testing for and ensuring safe working atmospheres, in particular: permit controlled confined spaces, and prior to and during hot work for both open and enclosed spaces. It will enable one to read and interpret correctly information as obtained from the gas detection means available. The gas tester course teaches students how to safely monitor the atmosphere, check oxygen level, flammable gas and toxic gas before entering the atmosphere. 

Target Audience

Safety Officer, Deck officers, Management Level Officers who would like to be Authorised Gas Tester.  agt authorised gas free tester and monitor

Course Content

 

AGT – Module 1 – Authorised Gas Tester 

(1) Confined space criteria

(2) The type of operations being tested for flammable and toxic gases

(3) The hazards of operations within an oxygen-enriched, oxygen-deficient, toxic or flammable environment

(4) Carrying out a suitable and sufficient risk assessments

(5) Understand the safe systems of work, how to work within the safe system of work and the associated responsibilities

(6) The implications of statutory and organisational requirements

(7) Interpreting operational requirements

(8) How to select, use and care for PPE and RPE

(9) Accessing and interpreting operational instructions

(10) The operating principles of atmosphere monitoring and measuring equipment and failure modes

(11) The strengths and weaknesses of various types of atmospheric flammable and toxic gas detection equipment

(12) Correct selection of aspirating or non-aspirating detectors to obtaining representative atmosphere sample

(13) Equipment required for testing for hydrocarbons in inert atmospheres

(14) Gas detector pre-start checks

(15) Determining the extent of the test boundaries

(16) Calibrating the instruments used in atmospheric testing

(17) Sources of assistance during the event of damaged or defective equipment

(18) Interpreting normal and abnormal results

(19) Documenting the results and advising relevant personnel

AGT – Module 2 – Testing for flammable gas in preparation for hot work

(1) Hot work (any operation involving naked flames or producing heat and/or sparks or any operation that has spark potential)

(2) Type of operations being tested for flammable and toxic gases

(3) The principles of hot work gas testing

(4) The hazards and properties of flammable gases

(5) Acceptable levels of flammable gases and the correct amount of oxygen

(6) Carrying out a suitable and sufficient risk assessment

(7) Using safe systems of work and understanding the associated responsibilities

(8) The implications of organisational and statutory requirements

(9) Detectors used for the flammable product

(10) How to set up the relevant detectors for each gas testing application and confirm functioning correctly

(11) The range and frequency of tests and monitoring and retesting requirements

(12) Where to site portable or transportable equipment that will be used to continuously monitor the atmosphere

AGT – Module 3 – Confined Space Testing

(1) The hazards and properties of flammable and toxic gases

(2) The behaviour of different gases

(3) The range and frequency of tests and monitoring and retesting requirements after initial entry

(4) Acceptable levels of flammable gases and the correct amount of oxygen

(5) The implications of WEL for toxic gases and LEL for flammable gases

(6) How to set up the relevant detectors for each gas testing application and confirm functioning correctly

(7) Performing Gas tests in sequential order

(8) How to obtain representative atmosphere sample

(9) Taking various samples to locate varying concentrations of gases and vapours

(10) Importance of sampling confined spaces at a distance

(11) Testing flammable gases in inert atmospheres

(12) Where to site portable or transportable equipment that will be used to continuously monitor the atmosphere

AGT – Module 4 – Gas Monitoring for Hotwork Sites

(1) Hot work (any operation involving naked flames or producing heat and/or sparks or any operation that has spark potential)

(2) Confined space criteria

(3) The type of operations being tested for flammable and toxic gases

(4) Roles and responsibilities of the Fire Watch

(5) Roles and responsibilities of the Stand By person

(6) Responsibilities of the Gas Monitor role

(7) How to select, use and care for PPE

(8) How to work within the safe system of work

(9) The hazards and properties of flammable gases

(10) The behaviour of different flammable and toxic gases

(11) The potential arrival of flammable gas or vapour clouds at the hot work site

(12) Impact of environmental changes on working conditions

(13) Importance of checking controls on the equipment are as specified

(14) Importance of regular communication

(15) Sources of assistance and specialist support

(16) Completion of relevant documentation

GMT – MODULE 1 Gas Monitoring for Hotwork Sites

(1) Hot work (any operation involving naked flames or producing heat and/or sparks or any operation that has spark potential)
(2) Confined space criteria
(3) The type of operations being tested for flammable and toxic gases
(4) Roles and responsibilities of the Fire Watch
(5) Roles and responsibilities of the Stand By person
(6) Responsibilities of the Gas Monitor role
(7) How to select, use and care for PPE
(8) How to work within the safe system of work
(9) The hazards and properties of flammable gases
(10) The behaviour of different flammable and toxic gases
(11) The potential arrival of flammable gas or vapour clouds at the hot work site
(12) Impact of environmental changes on working conditions
(13) Importance of checking controls on the equipment are as specified
(14) Importance of regular communication
(15) Sources of assistance and specialist support
(16) Completion of relevant documentation

Gas Freeing Methods in Tankers

Term Definition – 
Inerting: Introduction of IG into tank for attainting inert condition

Gas-freeing:  Introduction of fresh air into a tank to remove toxic, flammable and inert
gases and to increase oxygen content to 21% by volume

Purging: Introduction of IG into a tank already in the Inert condition to

– Further reducing the existing oxygen content and /or
– Reducing the existing HC content to a level below which combustion cannot be supported if air is subsequently introduced into tank
– Reduce Toxic gas (H2S etc.) vapors in tank

Three operations which involve replacement of gas in cargo tanks namely

 Inerting
 Purging
 Gas-freeing

In each of these replacement operations one of the two process can predominate
 Dilution (Which is mixing process)
 Displacement (Which is layering process)

These two processes have a marked effect on the method of monitoring the tank atmosphere and the interpretation of results Below show that an understanding on the nature of the gas replacement process actually taking place within the tank is necessary for the correct interpretation of the reading shown on the appropriate gas sampling instrument.

Dilution
 Incoming gas mixes with the original gases to for a homogenous mixture throughout the tank
 Result is that the concentration of the original gas decreases exponentially
 Actual rate of the gas replacement depends upon
   – the volume flow of the incoming gas
   – its entry velocity
   – dimensions of the tank
 For complete gas replacement it is important that entry velocity of the incoming gas is high enough for the jet to reach bottom of the tank
 It is important to confirm ability of the every IG System using this principle to achieve the required degree of gas replacement throughout the tank
 Below diagram shows an inlet and outlet configuration for the dilution process and illustrates the turbulent nature of the gas flow within the tank
 Curves of the gas concentration against time for the three different sampling positions

Displacement
 Ideal replacement requires a stable horizontal interface between the lighter gas entering at the top of the tank and the heavier gas being displaced from the bottom of the tank through some suitable piping arrangement
 This method requires a relatively low entry velocity of gas and in practice more than one volume change is necessary
 It is therefore important to confirm the ability of every installation using the principle to achieve the required degree of gas replacement throughout the tank
 Below diagram shows an inlet and outlet configuration for the displacement process and illustrates the turbulent nature of the gas flow within the tank
 Curves of the gas concentration against time for the three different sampling levels

Arrangement for Inerting, Purging and Gas freeing
Application of principles of displacement and dilution to the specific installation depends on variety of factors

 Results of laboratory tests
 Whether or not purging of hydrocarbon gas is required in every tank on every voyage
 Method of venting cargo tank vapours

Several arrangements are possible. One feature which should be common to all is that the inlet and outlet points should be so located that efficient gas replacement can take place throughout the tank

There are three principal arrangement

It will be noted that all three arrangement can be used for inerting , purging and gas freeing and that a particular ship design may in corporate more than one arrangement

Arrangement A
Gases are both introduced and vented from the top of tank. This is the simplest arrangement. Gas replacement is by dilution method. The incoming gas should always enter the tank in such a way as to achieve maximum penetration and thorough mixing throughout the tank. Gases can be vented through a vent stack on each tank or through a common vent main

Arrangement B
Gas is introduced at the bottom of the tank and vented from the top. Gas replacement is by the dilution method. This arrangement introduces the gas through a connection between the inert gas deck main (just forward of the mechanical non return valve) and the bottom cargo lines . A special fixed gas freeing fan may also be fitted. Exhaust gas may be vented
through individual vent stacks or if valves are fitted to isolate each cargo tank from the inert gas main, through this main to mast riser or PV Valve.

Arrangement C
Gas is introduced at the top of the tank and discharged from the bottom. This arrangement permits the displacement although the dilution method may predominate if the density difference between the incoming and existing gases is small or the gas inlet velocity is high. The inert gas inlet point is often led horizontally into a tank hatch in order to minimize turbulence at the interface. The outlet point is often a specially fitted purge pipe extending from within 1m of the bottom plating to 2m
above deck level (to minimize the amount of vapour at deck level).

Course	Fee INR	Duration	Course Timing	Date Commence	Remarks
AGT	10,000	1 day	10:00-18:00	On Demand
GMT	10,000	1 day	10:00-18:00	On Demand
GAS FREE	10,000	1 day	10:00-18:00	On Demand