CITB Specialist Plumbing (JIB) Test

Sample question 1 · Plumbing (JIB)

According to HSE, which water temperature range suits the growth of legionella bacteria?

1. A0 to 10 degrees C
2. B20 to 45 degrees CCorrect answer
3. C50 to 70 degrees C
4. D70 to 90 degrees C

Why B: HSE says the risk from legionella increases where the water temperature in all or some parts of the system is between 20 and 45 degrees C, which is suitable for growth. Keeping water outside that band is the basis of temperature control in hot and cold water systems.

Sample question 2 · Plumbing (JIB)

You are about to cut a metal gas pipe to fit a new section. Where it is necessary to prevent danger, what does regulation 10 of the Gas Safety (Installation and Use) Regulations 1998 require?

1. AA residual current device fitted to the site supply before you cut the pipe
2. BThe main earthing conductor disconnected at the consumer unit before you cut
3. CAn insulating joint fitted either side of the new section, so the pipe run cannot carry a current
4. DA suitable bond across the cut to maintain electrical continuity until permanent continuity is restoredCorrect answer

Why D: Regulation 10 of the Gas Safety (Installation and Use) Regulations 1998 says that in any case where it is necessary to prevent danger, no person shall carry out work in relation to a gas fitting without using a suitable bond to maintain electrical continuity until the work is completed and permanent electrical continuity has been restored. Cutting the pipe can break the earth path, so a temporary continuity bond goes on before the cut, not after it.

Sample question 3 · Plumbing (JIB)

A building manager asks you to deal with the dead legs on a water system. Which of these does HSE describe as a dead leg?

1. AA redundant length of pipe closed at one end that water cannot flow through at all, left over from an old run
2. BAny length of pipe that carries cold water only, wherever it runs in the building
3. CA pipe leading to an outlet that water does flow through, but the outlet is unused or rarely usedCorrect answer
4. DThe length of pipe between the boiler and the cylinder coil, which sits hot all day

Why C: HSE defines a dead leg as a pipe leading to an outlet which water flows through but the outlet is unused or rarely used. A dead or blind end is different: HSE defines it as a redundant length of pipe closed at one end, which water cannot flow through. HSE says to remove dead ends and blind ends, and to flush dead legs regularly.

Sample question 4 · Plumbing (JIB)

An unvented hot water storage vessel holds more than 15 litres. Under Schedule 2 to the Water Supply (Water Fittings) Regulations 1999, what must be provided on it?

1. AA temperature relief valve, or a combined temperature and pressure relief valve, located directly on the vesselCorrect answer
2. BA drain cock at the lowest point of the vessel, so the cylinder can be emptied down before any work is done on it
3. CA secondary return pump on the vessel to keep the hot water moving round the flat
4. DAn open vent pipe rising above the cold feed cistern that feeds the vessel in the loft

Why A: Paragraph 23(1) of Schedule 2 to the Water Supply (Water Fittings) Regulations 1999 requires a temperature relief valve or combined temperature and pressure relief valve on every unvented hot water storage vessel with a capacity greater than 15 litres. Paragraph 23(2)(a) says it must be located directly on the vessel, in an appropriate location and with sufficient discharge capacity, so the stored water cannot exceed 100 degrees C. An unvented vessel is by definition one with no vent pipe to the atmosphere, which is what rules out option D.

Sample question 5 · Plumbing (JIB)

Under the Gas Safety (Installation and Use) Regulations 1998, what is the rule on manually operated flue dampers and domestic gas appliances?

1. AOne may be fitted provided the householder is shown how to work it and told to leave it open when the boiler is running
2. BOne may be fitted provided a carbon monoxide alarm goes in the same room as both the appliance and the flue it serves
3. COne may be fitted provided it is checked every 12 months at the annual service, along with the rest of the boiler flue
4. DNone may be installed to serve a domestic gas appliance, and where a flue already has one, the appliance may only go on it if the damper is permanently fixed openCorrect answer

Why D: Regulation 32(2) of the Gas Safety (Installation and Use) Regulations 1998 says no person shall install a manually operated damper to serve a domestic gas appliance, and regulation 32(3) says no person shall install a domestic gas appliance to a flue which incorporates a manually operated damper unless that damper is permanently fixed in the open position. A damper someone can close is a flue someone can block. By contrast regulation 32(1) allows an automatic damper, but only where it is interlocked with the gas supply so the burner cannot run if the damper fails anywhere but open.

Sample question 6 · Plumbing (JIB)

A sealed heating circuit has been dosed with an ethylene glycol antifreeze. Which fluid category does Schedule 1 to the Water Supply (Water Fittings) Regulations 1999 put that water in?

1. ACategory 1, because it came from the mains to start with
2. BCategory 2, because the change is to its taste and smell
3. CCategory 5, because it holds pathogenic organisms or waste
4. DCategory 3, because it holds substances of low toxicityCorrect answer

Why D: Fluid category 3 is fluid that is a slight health hazard because of the concentration of substances of low toxicity, and Schedule 1 names fluid containing ethylene glycol as an example.

Sample question 7 · Plumbing (JIB)

A temperature relief valve on a hot water vessel has just discharged. Under Schedule 2 to the Water Supply (Water Fittings) Regulations 1999, what must the valve then do?

1. AShut off the cold feed to the whole vessel until reset
2. BClose again automatically after the discharge of waterCorrect answer
3. CStay open until someone resets it by hand on site
4. DLock itself shut so it cannot discharge a second time

Why B: Paragraph 22(1) requires every expansion valve, temperature relief valve or combined temperature and pressure relief valve connected to a fitting or appliance to close automatically after a discharge of water.

Sample question 8 · Plumbing (JIB)

A building has two separately occupied units fed from one supply pipe. Under Schedule 2 to the Water Supply (Water Fittings) Regulations 1999, when must backflow prevention be provided on that pipe?

1. AOnly where the pipe is laid more than 1350 mm below the surface of the ground
2. BOnly where the supply pipe is made of plastics instead of copper or gunmetal
3. COnly where one of the two units holds more than 230 litres of stored water
4. DWhere it is needed to prevent backflow between the separately occupied premisesCorrect answer

Why D: Paragraph 15(4)(a) requires backflow prevention on any supply pipe or distributing pipe where it is necessary to prevent backflow between separately occupied premises.

Sample question 9 · Plumbing (JIB)

You have finished the simple water system in a small rented house. When does HSE say it should be thoroughly flushed?

1. AAt no point, because a new and simple system cannot hold bacteria
2. BBefore use, and as close to the start of occupation as possibleCorrect answer
3. CStraight after the pressure test, however long before occupation
4. DOnce the tenants have lived there for a month and used the system

Why B: HSG274 Part 2 para 2.43 says small developments with simple water systems, including rented domestic houses, should be thoroughly flushed before use, as close to occupation as possible to minimise the possibility of microbial growth.

Sample question 10 · Plumbing (JIB)

A hot water system has a duty circulating pump and a standby pump. How often does HSE say the standby pump should be used?

1. AWhen the duty pump breaks down and needs repairing
2. BOnce a year, as part of the annual calorifier inspection
3. COnce a quarter, at the same time as showers are descaled
4. DAt least once each week, to avoid water stagnating in itCorrect answer

Why D: HSG274 Part 2 para 2.61 says standby pumps should be used at least once each week to avoid water stagnation.