CCN TEST
- Thread starter boabyboy
- Start date
Probably get shot but what the hell it is all to do with gas safety, or thats my excuse anyway 
6a. Tightness testing & purging of domestic sized natural gas installations.
Satisfactory completion of the assessment in this Core Competence will provide evidence of competence in testing for tightness & purging of domestic sized natural gas installations upto
28mm.
PERFORMANCE CRITERIA :
1. Testing New Installations with
gas or air ( IGE / UP / 1B )
(i) installation is inspected visually to ensure joints have been made correctly & there are no open ends
(ii) isolate any connected appliance from the installation
(iii) connect the selected & assembled pressure gauge to suitable test point if testing with gas or if with air branch of test Tpiece
(iv) if using gas carry out letby
test of the isolation valve (MCV) or if fitted (TV)
(v) raise the pressure to approximately 10 mbar by slowly opening the isolation valve
(vi) turn off the gas supply by closing the isolation valve
(vii) if pressure rises by more than 0.5 mbar over the next 1 minute period letby
may be occurring
(viii) the isolation valve should be checked by disconnecting its outlet union & applying LDF to the valve barrel (oral question should satisfy this criteria)
(ix) on satisfactory completion of letby
test slowly turn on gas or air supply & raise pressure to 20 mbar
(x) turn off gas or air supply
(xi) allow 1 minute for temperature stabilisation
(xii) check that there is no pressure drop over the next 2 minute period & no smell of gas
(xiii) if the installation fails the test, trace & repair escape & retest
the installation
(xiv) if the tightness test is successful reopen
isolation valves to appliances & ensure any SSOV is open
(xv) bring pressure back up to 20 mbar
(xvi) allow 1 minute for temperature stabilisation
(xvii) check that there is no pressure drop over the next 2 minute period & no smell of gas
(xviii) if the installation fails the test, trace & repair escape & retest
the installation
(xix) remove pressure gauge & reseal
test point
(xx) when connected to gas test
pressure test point, MCV outlet connection, regulator connections & where appropriate TV connections with LDF or
suitable gas detector
(xxi) installation is purged in accordance with IGE/UP/1B (section 6)
(xxii) the test results are recorded
2. a gas escape is correctly located & repaired
KNOWLEDGE & UNDERSTANDING The candidate must be able correctly to answer gas safety questions in the following topics relating
CRITERIA: to domestic gas tightness testing & purging:
1. correct selection & reading of pressure gauges
2. allowed pressure drops for existing installations related to meter size/type with appliances connected to the gas supply & not isolated
3. identification of no perceptible movement on the gauge ( 0·5 mbar water gauge & 0·3 mbar electronic gauge)
4. allowed pressure drop for existing installation to be tested including emergency control valve but no meter is installed e.g. flat where supply is not individually
metered
5. electronic token meter tamper devices & their effect on tightness testing
6. procedures for dealing with an emergency / meter control that is letting by
7. actions to be taken when a smell of gas persists (a) after completion of a satisfactory soundness test (b) when the emergency / meter control is turned off
8. tightness testing requirements when carrying out gas work on pipework over 28mm
6b. Tightness testing & purging of domestic sized natural gas installations.
Satisfactory completion of the assessment in this Core competence will provide evidence of competence in testing for tightness & purging of domestic sized natural gas installations.
PERFORMANCE CRITERIA:
2. Additional tests required where the supply MOP exceeds 75 mbar, but a test valve (TV) is not fitted ( IGE/UP/1B)
a) LetBy
Test on the MCV
(i) turn off gas supply at the MCV
(ii) connect gauge to a suitable point on the system
(iii) release any pressure from the system from a suitable point in the installation & reseal
(iv) any release mechanism on the regulator is held open to balance the pressure
(v) the gauge is observed for 1 minute, no perceptible movement is allowed (more than 0·5 mbar water gauge)
(vi) if the valve is lettingby
the test is suspended, installation made safe & the National Gas Emergency Service Call Centre notified
b) LetBy
Test on the Gas Regulator
(i) the release mechanism on the regulator is returned to its off position
(ii) the MCV is reopened
(iii) the gauge is observed for 1 minute, no perceptible movement is allowed (more than 0·5 mbar water gauge)
(iv) if the regulator is lettingby
the test is suspended, installation made safe & the National Gas Emergency Service Call Centre notified
(v) after successful completion of letby
tests the gas supply is turned off & the pressure from the system released
(vi) the MCV is opened VERY SLOWLY at the same time as operating any reset
lever on the regulator raising the pressure to 19mbar (to prevent
lockup)
(vii) the gas supply is turned off & test continued as previously in 6a
6a. Tightness testing & purging of domestic sized natural gas installations.
Satisfactory completion of the assessment in this Core Competence will provide evidence of competence in testing for tightness & purging of domestic sized natural gas installations upto
28mm.
PERFORMANCE CRITERIA :
1. Testing New Installations with
gas or air ( IGE / UP / 1B )
(i) installation is inspected visually to ensure joints have been made correctly & there are no open ends
(ii) isolate any connected appliance from the installation
(iii) connect the selected & assembled pressure gauge to suitable test point if testing with gas or if with air branch of test Tpiece
(iv) if using gas carry out letby
test of the isolation valve (MCV) or if fitted (TV)
(v) raise the pressure to approximately 10 mbar by slowly opening the isolation valve
(vi) turn off the gas supply by closing the isolation valve
(vii) if pressure rises by more than 0.5 mbar over the next 1 minute period letby
may be occurring
(viii) the isolation valve should be checked by disconnecting its outlet union & applying LDF to the valve barrel (oral question should satisfy this criteria)
(ix) on satisfactory completion of letby
test slowly turn on gas or air supply & raise pressure to 20 mbar
(x) turn off gas or air supply
(xi) allow 1 minute for temperature stabilisation
(xii) check that there is no pressure drop over the next 2 minute period & no smell of gas
(xiii) if the installation fails the test, trace & repair escape & retest
the installation
(xiv) if the tightness test is successful reopen
isolation valves to appliances & ensure any SSOV is open
(xv) bring pressure back up to 20 mbar
(xvi) allow 1 minute for temperature stabilisation
(xvii) check that there is no pressure drop over the next 2 minute period & no smell of gas
(xviii) if the installation fails the test, trace & repair escape & retest
the installation
(xix) remove pressure gauge & reseal
test point
(xx) when connected to gas test
pressure test point, MCV outlet connection, regulator connections & where appropriate TV connections with LDF or
suitable gas detector
(xxi) installation is purged in accordance with IGE/UP/1B (section 6)
(xxii) the test results are recorded
2. a gas escape is correctly located & repaired
KNOWLEDGE & UNDERSTANDING The candidate must be able correctly to answer gas safety questions in the following topics relating
CRITERIA: to domestic gas tightness testing & purging:
1. correct selection & reading of pressure gauges
2. allowed pressure drops for existing installations related to meter size/type with appliances connected to the gas supply & not isolated
3. identification of no perceptible movement on the gauge ( 0·5 mbar water gauge & 0·3 mbar electronic gauge)
4. allowed pressure drop for existing installation to be tested including emergency control valve but no meter is installed e.g. flat where supply is not individually
metered
5. electronic token meter tamper devices & their effect on tightness testing
6. procedures for dealing with an emergency / meter control that is letting by
7. actions to be taken when a smell of gas persists (a) after completion of a satisfactory soundness test (b) when the emergency / meter control is turned off
8. tightness testing requirements when carrying out gas work on pipework over 28mm
6b. Tightness testing & purging of domestic sized natural gas installations.
Satisfactory completion of the assessment in this Core competence will provide evidence of competence in testing for tightness & purging of domestic sized natural gas installations.
PERFORMANCE CRITERIA:
2. Additional tests required where the supply MOP exceeds 75 mbar, but a test valve (TV) is not fitted ( IGE/UP/1B)
a) LetBy
Test on the MCV
(i) turn off gas supply at the MCV
(ii) connect gauge to a suitable point on the system
(iii) release any pressure from the system from a suitable point in the installation & reseal
(iv) any release mechanism on the regulator is held open to balance the pressure
(v) the gauge is observed for 1 minute, no perceptible movement is allowed (more than 0·5 mbar water gauge)
(vi) if the valve is lettingby
the test is suspended, installation made safe & the National Gas Emergency Service Call Centre notified
b) LetBy
Test on the Gas Regulator
(i) the release mechanism on the regulator is returned to its off position
(ii) the MCV is reopened
(iii) the gauge is observed for 1 minute, no perceptible movement is allowed (more than 0·5 mbar water gauge)
(iv) if the regulator is lettingby
the test is suspended, installation made safe & the National Gas Emergency Service Call Centre notified
(v) after successful completion of letby
tests the gas supply is turned off & the pressure from the system released
(vi) the MCV is opened VERY SLOWLY at the same time as operating any reset
lever on the regulator raising the pressure to 19mbar (to prevent
lockup)
(vii) the gas supply is turned off & test continued as previously in 6a
Just like the real thing - plenty of ambiguous questions with multiple correct answers
Last ACS assessment I was instructed to put down the incorect answers in order to pass
such was the quality of the questions/answers.
Last ACS assessment I was instructed to put down the incorect answers in order to pass
such was the quality of the questions/answers.bster said:If hes studying plumbing and gas then he really does need to buy some books, what course is he doin? - I'm coming to the end of my NVQ2+3 plumbing nad heating, so if he wants some advice on books... then ask me
bster if you want anything thing on gas just email me, you know how by now
ahh don't you just love a good D.J . 
e mail me and i will explain might even send yer a pic of the ugly old git
not dead yet then yer old git
doitall said:
not dead yet then yer old git
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