Properties and combustion Gas Supplies 704°C ignition temperature Stages of the combustion process Note: nitrogen is also present within the atmosphere but plays no part in the combustion process and therefore can be ignored 5–15% gas in air Fuel (methane) Stage 1: requirements for combustion to occur outer mantle reaction zone Stage 2: the oxidation of the fuel within the appliance secondary air supply unburnt gas gas/air mixture carbon dioxide water vapour primary air drawn in gas injector gas supply The operation of an aerated burner Final stage: products passing out through the flue pipe Properties and combustion of natural gas From Plumbing (3rd edition), R.D. Treloar, page 191 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Gas safety regulations existing flue 10 mm2 cable Regulation No. 8 The construction of the dormer window will affect the effective discharge of flue gases from the building unless the terminal is raised Regulation No. 10 Temporary bonding wire required when removing a section of pipework proposed dormer within 1.5 m pipe sleeve mastic seal to one side of sleeve only Regulation No. 30 Open flued appliances are not permitted to be installed in bathrooms screwdriver Regulation No. 19 Pipes must be sleeved when passing through a wall cavity Regulation No. 33 Burner pressure to be adjusted in accordance with manufacturer’s instructions dust cap gas regulator to gas burner inlet gas supply Gas safety regulations From Plumbing (3rd edition), R.D. Treloar, page 193 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas supply to the consumer Gas Supplies meter regulator gas meter pipe capped off high level vent meter control valve GRP protective sleeve Semi-concealed meter box 375 mm min dpc. PE service pipe 0.5 m min 1.0 m max expansion joint in vertical section Surface mounted meter box Sleeve sealed internally sleeve riser low level vent 1/2 hour fire resistant access panel Sunken meter box Gas supply to the consumer steel base plate to support weight of riser incoming gas supply From Plumbing (3rd edition), R.D. Treloar, page 195 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com Internal riser

Gas Supplies Sizing of gas pipework boiler cooker 17 kW 14.6 kW gas meter D 1.5 m E 2.0 m 0.6 m A C 4.0 m 3.0 m 0.6 m B 3.0 m fire 5 kW Sizing of gas pipework From Plumbing (3rd edition), R.D. Treloar, page 197 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas meter with medium pressure regulator and test valve Gas Supplies Gas meter with low pressure regulator Gas meter with medium pressure regulator and test valve meter bracket gas regulator Tightness testing gas carcass prior to meter installation test nipple clamping peg or plug cock consumer’s emergency control cock test dial installation pipework gas meter hand pump incoming gas supply Tightness testing installation with gas meter fitted manometer Tightness testing and purging From Plumbing (3rd edition), R.D. Treloar, page 201 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Gas controls 1 Typical multi-functional valve turn clockwise to increase pressure pressure adjusting screw dust cap breather hole test nipple diaphragm gas inlet section through gas regulator gas burner manometer Typical multi-functional valve working pressure and standing pressure if all appliances are turned off burner pressure reading button to operate thermoelectric valve main solenoid valve Thermoelectric valve pilot flame thermocouple valve ‘X’ electromagnet regulator Gas regulator section through a multi-function gas valve Gas controls 1 From Plumbing (3rd edition), R.D. Treloar, page 205 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Oxygen depletion sensor Gas Supplies rod type thermostat weep pipe Gas relay valve diaphragm bypass orifice diaphragm coil of wire iron plunger thermistor located in draught diverter reset plunger Low pressure cut-off Atmosphere sensing device Solenoid valve pilot flame spark electrode pilot thermocouple thermocouple primary air port Oxygen depletion sensor thermocouple interruptor lack of oxygen at the flame primary air port causes the flame to alter, thus fails to impinge onto the thermocouple causing the gas valve to close From Plumbing (3rd edition), R.D. Treloar, page 207 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com Gas controls 2

Gas Supplies Flame supervision devices Liquid vapour device two dissimilar metals bonded together Liquid vapour device bellows phial valve spring Bi-metallic strip bypass orifice reset button pilot tube A B C Thermoelectric, liquid vapour and photo-electric flame supervision devices thermocouple solenoid Thermoelectric valve solenoid ac current dc current control box Note: this illustration simplifies the concept of flame rectification. Thus, once a flame is established an electrical circuit is formed Flame rectification device Flame supervision devices From Plumbing (3rd edition), R.D. Treloar, page 209 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Draught diverter situated Gas Supplies hot gases exit at high level terminal hot gases rise due to convection currents flue pipe 25 mm secondary flue non-combustible sleeve to maintain fire precaution draught diverter down draught primary flue cool air enters at low level air vent required for appliances over 7 kW 600 mm boiler casing draught diverter adverse conditions Draught diverter situated above a boiler diluent air drawn in (under normal conditions) diverter fitted separate from appliance diverter incorporated within appliance Open flued appliances From Plumbing (3rd edition), R.D. Treloar, page 211 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Terminal location for open flues high rise building wind direction Positive and negative pressure zones to be avoided for siting of flue terminals relying on natural flue draught Unless there is no wind this example will always be in a positive pressure zone irrespective of wind direction 600 mm 250 mm if less than 600 mm increase to above ridge location ridge terminal 600 mm Typical gas flue terminals 1.5 m 0.6 m 0.6 m 0.6 m 1.5 m roof pitch greater than 1.5 m 0.6 m parapet wall within 1.5 m Terminal location for open flues From Plumbing (3rd edition), R.D. Treloar, page 213 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Installation of pre-cast Materials and construction of open flues Gas Supplies chimney liner terminal flaunching clamping plate self tapping screw flue gases liner where single flue pipes with sockets are used the spigot should sit into the socket with the spigot uppermost register plate or glass fibre quilt twin wall flue pipe back boiler Installation of a flue liner A A liner secured to boiler and the joint made sound with fire cement first floor section A–A ground floor straight bonding block fire recess starter block Installation of pre-cast concrete flue blocks Materials and construction of open flues From Plumbing (3rd edition), R.D. Treloar, page 215 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

250 mm minimum debris collection space Gas Supplies heat exchanger 50 mm min closure plate radiants Traditional gas fire 250 mm minimum debris collection space flue way heat exchanger hearth Inset live effect fire fire back Decorative fuel effect fire Installation of gas fires From Plumbing (3rd edition), R.D. Treloar, page 217 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas cooker installation Gas Supplies angled bayonet socket looking down cooker hose cooker stability bracket 610 mm 150 mm 150 mm 760 mm 300 mm 50 mm minimum dimensions to be observed 20 mm 20 mm Gas cooker installation From Plumbing (3rd edition), R.D. Treloar, page 219 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Room sealed appliances 1 Natural draught appliance combustion products air inlet burner Natural draught appliance This design would no longer meet current legislation Room sealed boiler fan heat exchanger Natural draught terminal Note: a guard is required where the terminal is accessible (i.e. < 2 m from an accessible area) Fan assisted appliance Fan assisted terminal Room sealed appliances 1 From Plumbing (3rd edition), R.D. Treloar, page 221 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Room sealed appliances 2 Vertical room sealed appliances flue gases out flue gases out air intake air intake concentric flue/air duct parallel flue/air ducts (allows for greater flue length) Vertical room sealed appliances flue gas extract 150 mm maximum air intake twin wall or insulated flue pipe self closing door which, when closed, allows the electrical supply to pass to the boiler open flued appliance Balanced compartment Room sealed appliances 2 From Plumbing (3rd edition), R.D. Treloar, page 223 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Typical ventilator grilles Gas Supplies W A H A section A–A Typical ventilator grilles Typical terracotta air vent effective grille size: H x W x No. holes example: if the hole size was to measure 10 mm x 10 mm in the terracotta grille shown the effective free area would be 10 x 10 x 20 = 2000 mm2 (20 cm2) L B B W Typical sheet metal vent section B–B where a grille is installed within a cavity wall it must be made to bridge the gap of the cavity effective grille size: L x W x No. slots Ventilation requirements From Plumbing (3rd edition), R.D. Treloar, page 225 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Other flueing systems ‘Vertex’ or ‘Solver’ flue system flue gas outlet terminal outlet terminal secondary flue draught diverter main flue way 600 mm min air supply inlet 400 mm min appliance ‘Vertex’ or ‘Solver’ flue system primary flue Branched flued system appliance combustion products terminal air inlet Balanced flued appliances air inlet Se duct From Plumbing (3rd edition), R.D. Treloar, page 227 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com Other flueing systems U duct

Gas Supplies LPG supply LPG bulk tank installation Bulk tank supply 1st stage regulator 3 m (this distance may be reduced for small bulk tanks) pressure relief valve emergency control valve 2nd stage regulator and UPSO float LPG bulk tank installation OPSO Bulk tank supply automatic changeover valve 1 m 0.3 m 1 m 1 m 2 m drain UPSO OPSO valve minimum dimensions to be observed when siting LPG Cylinder supply From Plumbing (3rd edition), R.D. Treloar, page 229 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com LPG supply

Selection of LPG regulators Gas Supplies automatic change over valve and regulator pigtail LPG cylinder emergency control valve Selection of LPG regulators pressure adjusting screw Regulator diaphragm valve LPG regulators From Plumbing (3rd edition), R.D. Treloar, page 231 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Combustion analysis Gas analyser and remote printer hose bellows unit sampling probe Gas analyser and remote printer sampling tube plunger non-return valve ‘Draeger’ flue gas analyser sampling probe hand pump ‘Fyrite’ CO2 analyser Combustion analysis From Plumbing (3rd edition), R.D. Treloar, page 233 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Flue efficiency in gas appliances Spillage testing draught diverter issuing smoke piece of copper tube used to make suitable smoke match holder (to prevent burning hands) smoke match tube crushed close to provide suitable pocket flue pipe with a gas fire the smoke match is to be held along top edge of the radiants tube blocked off at end spillage occurring draught diverter no spillage indicated smoke match to be held at all edges of draught diverter Spillage testing open flued appliance From Plumbing (3rd edition), R.D. Treloar, page 235 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com Flue efficiency in gas appliances

Gas Supplies Commissioning of gas installations Handing over! From Plumbing (3rd edition), R.D. Treloar, page 237 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies From Plumbing (3rd edition), R.D. Treloar, page 239 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Typical line diagram to be used showing all pipe runs and valves >28 mm in size lugs welded to pipe ‘U’-bolt support to hold the pipe firm clip designed to allow vertical free movement. The pipe simply sits onto the bracket, hanging freely ‘U’-bolt support allowing for expansion Pipe roller and chair designed to allow horizontal free movement From Plumbing (3rd edition), R.D. Treloar, page 241 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com

Gas Supplies Dealing with gas installations which do not comply with current Regulations and Standards From Plumbing (3rd edition), R.D. Treloar, page 243 Copyright Blackwell Publishing Ltd, all rights reserved: www.blackwellpublishing.com