RGII 5-Year Competency Assessment flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Gas Safe Register

The UK statutory gas registration body (since 2009) that replaced CORGI; only registered businesses may legally carry out gas work in domestic and commercial premises.

CP12 Landlord Record

The Landlord Gas Safety Record issued after an annual safety check of gas appliances and flues in rented domestic premises; a copy is given to the tenant and records kept for two years.

ID Warning Notice

Immediately Dangerous classification: an appliance or installation posing an immediate risk; it is turned off, labelled with a warning notice, and the responsible person is informed.

AR Warning Notice

At Risk classification: a defect that could become dangerous; the appliance is labelled and the user advised, but the immediate risk to life is not present.

RIDDOR Gas Reporting

The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations require certain gas incidents, including dangerous gas fittings and deaths, to be reported to the HSE.

Natural Gas Relative Density

Natural gas (methane, G20) has a relative density of about 0.6, so it is lighter than air and tends to rise and disperse at high level.

LPG Relative Density

Liquefied petroleum gas (propane, G31) has a relative density of about 1.55, so it is heavier than air and accumulates at low level in pits and voids.

Methane Flammable Limits

Methane is flammable in air at approximately 5% to 15% by volume; below the lower limit the mixture is too lean, above the upper limit too rich, to ignite.

Propane Flammable Limits

Propane (G31) is flammable in air at approximately 2.1% to 9.5% by volume, a wider and lower range than methane, increasing leak hazard at low level.

Methane Combustion Equation

Complete combustion of methane: CH4 + 2O2 -> CO2 + 2H2O, requiring about 9.5 volumes of air per volume of gas for stoichiometric burning.

Gas Odorisation

Natural gas is odorised with a sulphur compound (typically THT) so leaks are detectable by smell at about one-fifth of the lower explosive limit.

Carbon Monoxide Properties

CO is colourless, odourless and tasteless; it binds haemoglobin about 200-250 times more readily than oxygen, causing chemical asphyxiation at low concentrations.

CO/CO2 Ratio Action Levels

Industry guidance: a flue CO/CO2 ratio above 0.004 indicates a potential problem; above 0.008 is generally At Risk; above 0.02 is Immediately Dangerous.

Excess Air Effect

Excess air dilutes flue products, lowering measured CO2; insufficient air raises CO and produces yellow, lazy flames and sooting.

Flue Flow Test

A smoke pellet test confirming the flue pulls combustion products clear of an open-flued appliance under normal conditions before the spillage test is performed.

Spillage Test

A test at the draught diverter of an open-flued appliance under worst-case conditions (doors, fans, extractors) confirming products do not spill into the room.

Room-Sealed Appliance Air

A room-sealed appliance draws combustion air directly from outside via a balanced or concentric flue, so it does not rely on room ventilation for combustion air.

Permanent Ventilation Sizing

Permanent openings for open-flued natural gas appliances are sized per BS 5440-2 and manufacturer instructions; a common guide is 5 cm2 free area per kW above 7 kW.

Domestic Gas Operating Pressure

Natural gas at the meter outlet is nominally 21 mbar (typically 19-23 mbar); appliance inlet pressure must be within the manufacturer's stated tolerance.

Domestic Pipework Pressure Drop

BS 6891 sizing limits the pressure drop from meter to appliance to about 1 mbar for natural gas, leaving adequate inlet pressure at the appliance.

Pipe Sleeving Requirement

Pipe passing through a wall, floor or cavity must be sleeved and sealed, with the sleeve vented where it enters a void, to prevent gas accumulation.

Buried Compression Fitting Rule

Compression fittings on gas pipework must remain accessible and must not be buried in walls or floors; inaccessible joints require approved alternatives.

Equipotential Bonding

Main protective bonding of the gas installation pipework near the meter is required to equalise potential and reduce spark risk; the connection must be to a suitable earth.

Tightness Test Sequence

A let-by test at operating pressure, a stabilisation period, then a pressure-loss test at the specified test pressure for the specified duration with no allowable drop.

IGEM/UP/1B Domestic Testing

The domestic tightness testing and purging standard; specifies test pressures, stabilisation and test durations for low-pressure domestic natural gas installations.

Gas Rate Check

Timed meter reading compared with the appliance data badge input; a metric meter reads m3 and an imperial meter reads cubic feet (1 ft3 = 0.0283 m3).

Appliance Data Badge

The label giving model, gas type and category (e.g. II2H3P), input and output in kW, and NOx class; used to confirm suitability for the gas supply.

Flue Terminal Clearances

BS 5440-1 sets minimum distances from flue terminals to openings and boundaries (e.g. 300 mm from an opening window); manufacturer instructions take precedence.

FSD Test Procedure

Extinguish the flame and confirm the flame supervision device closes the gas valve within the manufacturer's specified time, typically within 60 seconds on many domestic appliances.

Service Combustion Records

Recording CO/CO2 ratio, CO ppm, O2% and CO2% at each service allows comparison with previous readings to detect deterioration of combustion performance.

Low Inlet Pressure Diagnosis

Correct meter pressure with low appliance inlet pressure indicates a pipework restriction; low meter pressure indicates a supply-side fault rather than an appliance fault.

Gas Emergency Procedure

On a gas escape: turn off the ECV, extinguish flames, avoid electrical switches, ventilate, evacuate and call the National Gas Emergency Service on 0800 111 999.