G13 Foul Water 2nd Edition Amendment 10 PDF

Acceptable Solutions and Prepared by by the the Ministry Ministry of of Business, Business, Innovation Innovation and and E...

Acceptable Solutions and Prepared by by the the Ministry Ministry of of Business, Business, Innovation Innovation and and Employment Employment Verification Methods Prepared For New Zealand Building Code Clause G13 Foul Water G13  Status of Verification Methods and Acceptable Solutions Verification Methods and Acceptable Solutions are prepared by the Ministry of Business, Innovation and Employment in accordance with section 22 of the Building Act 2004. Verification Methods and Acceptable Solutions are for use in establishing compliance with the New Zealand Building Code. A person who complies with a Verification Method or Acceptable Solution will be treated as having complied with the provisions of the Building Code to which the Verification Method or Acceptable Solution relates. However, using a Verification Method or Acceptable Solution is only one method of complying with the Building Code. There may be alternative ways to comply. Defined words (italicised in the text) and classified uses are explained in Clauses A1 and A2 of the Building Code and in the Definitions at the start of this document. Enquiries about the content of this document should be directed to: Ministry of Business, Innovation and Employment PO Box 1473, Wellington. Telephone 0800 242 243 Email: [email protected] Verification Methods and Acceptable Solutions are available from www.building.govt.nz © Ministry of Business, Innovation and Employment 2023 This document is protected by Crown copyright, unless indicated otherwise. The Ministry of Business, Innovation and Employment administers the copyright in this document. You may use and reproduce this document for your personal use or for the purposes of your business provided you reproduce the document accurately and not in an inappropriate or misleading context. You may not distribute this document to others or reproduce it for sale or profit. The Ministry of Business, Innovation and Employment owns or has licences to use all images and trademarks in this document. You must not use or reproduce images and trademarks featured in this document for any purpose (except as part of an accurate reproduction of this document) unless you first obtain the written permission of the Ministry of Business, Innovation and Employment. 2 Document Status The most recent version of this document (Amendment 10), as detailed in the Document History, is approved by the Chief Executive of the Ministry of Business, Innovation and Employment. It is effective from 2 November 2023 and supersedes all previous versions of this document. The previous version of this document (Amendment 9) will cease to have effect on 1 November 2024. People using this document should check for amendments on a regular basis. The Ministry of Business, Innovation and Employment may amend any part of any Verification Method or Acceptable Solution at any time. Up-to-date versions of Verification Methods and Acceptable Solutions are available from www.building.govt.nz G13: Document History Date Alterations First published July 1992 Amendment 1 September 1993 pp. vii–viii, References p.25, Figure 3 p. xi, Definitions p. 31, Figure 7 Reprinted incorporating Amendment 1 October 1994 Amendment 2 1 December 1995 p. viii, References Amendment 3 28 February 1998 p. ii, Document History p. 1, 1.0.1 p. viii, References p. 21, 1.0.1 Second edition Effective from 1 October 2001 Document revised – second edition issued Amendment 1 Published March 2007 p. 2, Document History, Status pp. 9–10, Definitions Effective from 23 June 2007 p. 6, Contents p. 52A, AS3 1.0, 1.0.1, 1.0.2 pp. 7–8, References p. 55, Index Erratum 1 Effective from 23 June 2007 pp. 5–6, Contents pp. 50–51, AS2 7.0, 7.1 pp. 33–34, AS1 8.0, 8.1 Amendment 2 Effective from 21 June 2007 p. 2, Document History, Status p. 8, References pp. 3, 4, 4A, Building Code Clause p. 52A, VM4 p. 6, Contents p. 54, Index Amendment 3 Published 30 June 2010 p. 2, Document History, Status p. 37, G13/AS2 Table 1 Effective from 30 September 2010 pp. 7–8, References p. 42, G13/AS2 5.1.2 p. 11, G13/VM1 1.0.1 p. 50, G13/AS2 6.1.2 p. 13, G13/AS1 Table 1 p. 51, G13/AS3 1.0.1 p. 32, G13/AS1 6.1.1 pp. 54–55, Index p. 33, G13/AS1 6.2.2, 6.3.1, 6.3.2, 7.1.2, Table 7 Amendment 4 Effective from 10 October 2011 p. 2, Document History, Status p. 10, Definitions until 14 August 2014 p. 8, References p. 37, G13/AS2 Table 1 Amendment 5 14 February 2014 p. 2A, Document History, Status p. 44, G13/AS2 5.6.1 until 30 May 2017 pp. 7–8, References p. 51, G13/SA2 1.03 p. 9, Definitions p. 52A, 1.1.2 p. 35, G13/VM2 1.0.1 Amendment 6 Effective p. 8, References p. 37 G13/AS2 Table 1 1 January 2017 p. 31 G13/AS1 5.8.2, 5.8.3 p. 51 G13/AS3 2.0.1, 2.0.2 until 31 March 2019 p. 33 G13/AS1 6.4.1 Amendment 7 Effective from 30 November 2018 p. 8 References p. 50 G13/AS2 6.1.3 until 31 October 2019 p. 33 G13/AS1 7.1.3 p. 51 G13/AS3 2.0.1 2A  G13: Document History (continued) Date Alterations Amendment 7 Effective from 30 November 2018 p. 8 References p. 50 G13/AS2 6.1.3 until 31 October 2019 p. 33 G13/AS1 7.1.3 p. 51 G13/AS3 2.0.1 Amendment 8 Effective 27 June 2019 until p. 8 References p. 33 G13/AS1 6.4.1 3 November 2021 Amendment 9 Effective from 5 November 2020 p 6 Contents p. 40 G13/AS2 3.3.1, 3.3.2, 3.4.2 until 1 November 2024 p. 8 References p. 45 G13/AS2 Figure 7 p. 10 Definitions p. 50 G13/AS2 6.1.2 p. 13 G13/AS1 Table 1 pp. 51–52 G13 AS3 1.0 p. 31 G/13/AS1 5.8.2 pp. 53-54 Index p. 33 G13/AS1 6.2.2 Amendment 10 Effective 2 November 2023 pp. 7-8A References p. 37 G13/AS2 2.0.1, Table 1 p. 9 Definitions p. 38 G13/AS2 3.2.1, Figure 1, p. 13 G13/AS1 Table 1, 2.1.1 3.3.1, Figure 2 p. 20 G13/AS1 4.6.3 p. 40 G13/AS2 3.5.1, 3.5.2 p. 25 G13/AS1 4.7.4, 4.7.5 p. 51 G13/AS3 1.0.2 Note: Page numbers relate to the document at the time of Amendment and may not match page numbers in current document. 2B  C l a u s e G1 3 F O U L W AT E R New Zealand Building Code Clause G13 Foul Water The mandatory provisions for building work are contained in the New Zealand Building Code (NZBC), which comprises the First Schedule to the Building Regulations 1992. The relevant NZBC Clause for Foul Water is G13. 1992/150 Building Regulations 1992 75 FIRST SCHEDULE–continued Clause G13–FOUL WATER Provisions Limits on application OBJECTIVE G13.1 The objective of this provision is to: (a) Safeguard people from illness due to infection or contamination resulting from personal hygiene activities; and (b) Safeguard people from loss of amenity due to the presence of unpleasant odours or the accumulation of offensive matter resulting from foul water disposal. FUNCTIONAL REQUIREMENT G13.2 Buildings in which sanitary fixtures and sanitary appliances using water-borne waste disposal are installed must be provided with— (a) an adequate plumbing and draining system to carry foul water to appropriate outfalls; and (b) if no sewer is available, an adequate system for the stor- Amend 1 age, treatment, and disposal of Jun 2007 foul water. PERFORMANCE G13.3.1 The plumbing system shall be constructed to: (a) Convey foul water from buildings to a drainage system, (b) Avoid the likelihood of blockage and leakage, (c) Avoid the likelihood of foul air and gases entering buildings, and (d) provide reasonable access for maintenance and clearing blockages. G13.3.2 The drainage system shall: (a) Convey foul water to an appropriate outfall, (b) Be constructed to avoid the likelihood of blockage, D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 21 June 2007 3  F O U L W AT E R C lause G13 76 Building Regulations 1992 1992/150 FIRST SCHEDULE–continued Clause G13–FOUL WATER Provisions Limits on application (c) Be supported, jointed and protected in a way that will avoid the likelihood of penetration of roots or the entry of ground water, (d) Be provided with reasonable access for maintenance and clearance blockages, (e) Be ventilated to avoid the likelihood of foul air and gases accumulating in the drainage system and sewer, and (f ) Be constructed to avoid the likelihood of damage from superimposed loads or normal ground movement. G13.3.3 Where a sewer connection is available, the drainage system shall be connected to the sewer, and the connection shall be made in a manner that avoids damage to the sewer and is to the approval of the network utility operator. G13.3.4 If no sewer is available, facilities for the storage, treatment, and disposal of foul water must be constructed— (a) with adequate capacity for the volume of foul water and the frequency of disposal; and (b) with adequate vehicle access for collection if required; and (c) to avoid the likelihood of con- tamination of any potable water supplies in compliance with Clause G12 “Water sup- plies”; and (d) to avoid the likellihood of con- tamination of soils, ground water, and waterways except as permitted under the Amend 1 Resource Management Act Jun 2007 1991; and 4 21 June 2007 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  C l a u s e G1 3 F O U L W AT E R 1992/150 Building Regulations 1992 77? FIRST SCHEDULE–continued Clause G13–FOUL WATER Provisions Limits on application (e) from materials that are imper- vious both to the foul water for which disposal is required, and to water; and (f ) to avoid the likelihood of blockage and leakage; and (g) to avoid the likelihood of foul air and gases accumulating within or entering into build- ings; and (h) to avoid the likelihood of unauthorised access by people; and (i) to permit easy cleaning and maintenance; and (j) to avoid the likelihood of damage from superimposed loads or normal ground move- ment; and (k) if those facilities are buried Amend 1 underground, to resist hydro- Jun 2007 static uplift pressures. D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 21 June 2007 4A 4B C o n te nts G1 3 /VM1 /VM2 /VM4 & AS1 /AS 2/AS 3 F O U L W AT E R Contents Page Page 6.0 Installation 32 References 7 6.1 Jointing methods 32 Definitions 9 6.2 Pipe supports 33 Verification Method G13/VM1 11 6.3 Thermal movement 33 Sanitary Plumbing 6.4 Fire separation 33 1.0 Sanitary Plumbing 11 7.0 Watertightness 33 Acceptable Solution G13/AS1 13 7.1 Test methods 33 Sanitary Plumbing 1.0 Scope 13 Erratum 1 Jun 2007 2.0 Materials 13 Verification Method G13/VM2 35 2.1 Pipes, traps and fittings 13 Drainage 3.0 Water Traps 13 1.0 Drainage 35 3.1 Water trap requirements 13 Acceptable Solution G13/AS2 37 3.2 Water trap dimensions 14 Drainage 3.3 Water trap location 14 1.0 Scope 37 3.4 Floor outlets 15 2.0 Materials 37 4.0 Discharge Pipes 18 2.1 Fill materials 37 4.1 Layout 18 3.0 Design 37 4.2 Access for cleaning 18 3.1 Bends 37 4.3 Diameter 20 3.2 Junctions 37 4.4 Gradient 20 3.3 Gully traps 38 4.5 Fixture discharge pipes 20 3.4 Grease traps 40 serving waste water fixtures 3.5 Gradient of drains 40 4.6 Fixture discharge pipes 20 serving soil fixtures 3.6 Diameter of drains 42 4.7 Discharge stacks 24 4.0 Drain Ventilation 42 5.0 Venting 25 4.1 Ventilation requirements 42 5.1 Venting required 25 4.2 Diameter of drain vent pipe 42 5.2 Vent pipes 25 5.0 Installation 42 5.3 Diameter of vent pipes 25 5.1 Jointing 42 5.4 Gradient of vent pipes 29 5.2 Construction 42 5.5 Connection of vents to 29 5.3 Construction methods 42 fixture discharge pipes 5.4 Trench width 44 5.6 Discharge stack and relief vents 31 5.7 Termination of open vent pipes 31 5.8 Air admittance valves 31 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 23 June 2007 5  F O U L W AT E R C ontents G13/V M1/V M2/V M4 & AS 1/AS 2/AS 3 Page 5.5 Placing and compacting 44 5.6 Proximity of trench to building 44 5.7 Access points 44 5.8 Additional requirements for 49 drains installed under buildings 5.9 Access to drains under buildings 49 5.10 Disused drains 50 6.0 Watertightness 50 Erratum 1 Jun 2007 6.1 Testing 50 Acceptable Solution G13/AS3 51 Sanitary Plumbing and Drainage 1.0 AS/NZS 3500.2 51 Amends 1, 6, 9 Verification Method G13/VM4 52A On-Site Disposal 1.0 General 52A Amend 2 Jun 2007 1.1 Scope 52A Index 53 6 5 November 2020 M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T  R e fe re n ce s G1 3 /VM1 /VM2 /VM4 & AS1 /AS 2/AS 3 F O U L W AT E R References For the purposes of New Zealand Building Code (NZBC) compliance, the Standards and documents referenced in these Verification Methods and Acceptable Solutions (primary Amend 5 Feb 2014 reference documents) must be the editions, along with their specific amendments, listed below. Where these primary reference documents refer to other Standards or documents (secondary reference documents), which in turn may also refer to other Standards or documents, and so on (lower-order reference documents), then the version in effect at the date of publication of these Amend 4 Oct 2011 Verification Methods and Acceptable Solutions must be used. Amend 5 Feb 2014 Where quoted Standards New Zealand Amend 3 Sep 2010 NZS 3501: 1976 Specification for copper tubes for water, AS1 Table 1, gas, and sanitation AS2 Table 1 Amends: 1, 2, 3 NZS 3604: 2011 Timber framed buildings AS2 5.6.1 Amend 5 Feb 2014 NZS 4229: 2013 Concrete masonry buildings not requiring AS2 5.6.1 specific engineering design Amend 5 Feb 2014 NZS 4442: 1988 Welded steel pipes and fittings for water, AS2 Table 1 sewage and medium pressure gas Amend 3 Sep 2010 British Standards Institution BS EN 295:- Vitrified clay pipe systems for drains and sewers Part 1: 2013 Requirements for pipes, fittings and joints AS2 Table 1 BS EN 1124:- Pipes and fittings of longitudinally welded stainless steel pipes with spigot and socket for waste water systems Part 1: 1999 Requirements, testing, quality control AS1 Table 1, AS2 Table 1 Part 2: 2014 System S, forms and dimensions AS1 Table 1, Amend 10 AS2 Table 1 Nov 2023 BS 437: 2008 Specification for cast iron drain pipes, fittings and AS2 Table 1 their joints for socketed and socketless systems Amend 3 BS EN 12056:- Gravity drainage systems inside buildings. VM1 1.0.1 Sep 2010 Part 2: 2000 Sanitary pipework, layout and calculation Amend 9 BS EN 12380: 2002 Air admittance valves for drainage systems. AS1 5.8.2, Table 1 Nov 2020 Requirements, test methods and evaluation of conformity M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 2 November 2023 7  F O U L W AT E R R eferences G13/V M1/V M2/V M4 & AS 1/AS 2/AS 3 Where quoted Standards Australia AS 1432: 2004 Copper tubes for plumbing, gasfitting and drainage AS1 Table 1, Amend 10 applications AS2 Table 1 Nov 2023 Amend 3 Sep 2010 AS 1579: 2001 Arc welded steel pipes and fittings for water AS2 Table 1 and waste water AS 1589: 2001 Copper and copper alloy waste fittings AS1 Table 1 Amend 3 Sep 2010 AS 1646: 2007 Elastomeric seals for waterworks purposes AS2 Table 1 AS 1741: 1991 Vitrified clay pipes and fittings with flexible joints – AS2 Table 1 Amend 10 Sewer quality Nov 2023 Amend 3 Sep 2010 AS 2887: 1993 Plastic waste fittings AS1 Table 1 Amend 3 Sep 2010 AS 3571: 2009 Plastic piping systems – Glass reinforced AS2 Table 1 thermoplastics (GRP) systems based on unsaturated polyester (UP) resin – pressure and non-pressure Amend 4 Oct 2011 drainage and sewerage (ISO 10467: 2004 MOD) Amend 10 Amend: 1 Nov 2023 Amend 3 Sep 2010 AS 4139: 2003 Fibre reinforced concrete pipes and fittings AS2 Table 1 Amend 10 AS 4809: 2017 Copper pipe and fittings – Installation and commissioning AS2 Table 1 Nov 2023 Australian/New Zealand Standards Amends 3, 4, 9 AS/NZS 1260: 2017 PVC-U pipes and fittings for drain, waste and AS1 Table 1, Amend 9 Amends vent applications AS2 Table 1 Nov 2020 5, 6, 9 Amends 2 and 5 AS/NZS 1547: 2012 On-site domestic wastewater management VM4 1.1.2 AS/NZS 2032: 2006 Installation of PVC pipe systems AS1 6.1.1, 6.2.2, Amend: 1 6.3.1, 7.1.2 AS2 5.1.2, 6.1.2, Table 1 Amend 3 Sep 2010 Amend 4 AS/NZS 2033: 2008 Installation of polyethylene pipe systems AS1 Table 1 Oct 2011 Amend: 1, 2 Amend 10 AS/NZS 2280: 2020 Ductile iron pipes and fittings AS2 Table 1 Nov 2023 Amends 5, 6, 9 Amend: 1 Amend 4 Oct 2011 AS/NZS 2566:- Buried flexible pipelines AS2 Table 1 Part 2: 2002 Installation Amends 6 and 9 Amend: 1, 2, 3 Amend 1 Jun 2007 AS/NZS 3500:- Plumbing and drainage Part 2: 2021 Sanitary plumbing and drainage AS1 7.1.3, Amends Amend 10 5, 6, 7, 8 Amend: 1 Nov 2023 VM2 1.0.1 Comment, Amend 7 AS2 6.1.3, Nov 2018 Amends AS3 1.0, 1.0.1, 1.0.2 8 and 9 8 2 November 2023 M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T  R e fe re n ce s G1 3 /VM1 /VM2 /VM4 & AS1 /AS 2/AS 3 F O U L W AT E R Where quoted AS/NZS 3518:2013 Acrylonitrile butadiene styrene (ABS) compounds, AS2 Table 1 pipes and fittings for pressure applications Amend 1 Jun 2007 Amends 6 and 9 Amend: 1 AS/NZS 4058: 2007 Pre cast concrete pipes (pressure and non pressure) AS2 Table 1 AS/NZS 4130: 2018 Polyethylene (PE) pipe for pressure applications AS2 Table 1 Amend 9 Nov 2020 Amend: 1 Amend 10 Nov 2023 Amend 3 AS/NZS 4401: 2006 High density polyethylene (PE-HD) pipes and AS1 Table 1 Sep 2010 fittings for soil and waste discharge (low and high temperature) systems inside buildings Amend 6 AS/NZS 4936: 2002 Air Admittance valves for use in sanitary plumbing AS1 5.8.2, Table 1 Oct 2016 and drainage systems. AS/NZS 5065: 2005 Polyethylene and polypropylene pipe and fittings AS2 Table 1 for drainage and sewerage applications Amends 4 and 9 Amend: 1, 2 AS/NZS 7671: 2010 Plastics piping systems for soild and waste discharge AS1 Table 1 (low and high temperature) inside buildings – Amend 10 Polypropylene (PP) Nov 2023 American Society of Sanitary Engineers ASSE 1050: 2009 Performance requirements for stack air admittance AS1 5.8.2, Table 1 valves for sanitary drainage systems ASSE 1051: 2009 Performance requirements for individual and AS1 5.8.2, Table 1 branch type air admittance valves for sanitary Amend 9 Nov 2020 drainage systems M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 2 November 2023 8A 8B  D e f i n i tio n s G1 3 /VM1 /VM2 & AS1 /AS2 / AS 3 F O U L W AT E R Definitions This is an abbreviated list of definitions for the words or terms particularly relevant to these Amend 1 Jun 2007 Verification Methods and Acceptable Solutions. The definitions for any other italicised words may Amend 5 Feb 2014 be found in the New Zealand Building Code Handbook. Access chamber A chamber with working and frequency of discharge from a sanitary space at drain level through which the drain fixture or sanitary appliance. passes either as an open channel or as a Drain A pipe normally laid below ground level pipe incorporating an inspection point. including fittings and equipment and Access point A place where access may be intended to convey foul water or surface made to a drain or discharge pipe for water to an outfall. inspection, cleaning or maintenance; and Drain vent pipe Any pipe which is intended to may include a cleaning eye, inspection permit the movement of air into and out of point, rodding point, inspection chamber or the drain and sewer. access chamber. Fixture An article intended to remain permanently Adequate Adequate to achieve the objectives attached to and form part of a building. of the building code. Fixture discharge pipe A discharge pipe that Air admittance valve A valve that allows air is used to convey waste from a single to enter but not to escape in order to limit sanitary fixture or sanitary appliance to a pressure fluctuations within the sanitary branch discharge pipe, a discharge stack, or plumbing or drainage system. directly to a drain. It does not include any Branch discharge pipe A discharge pipe that pipes forming part of a sanitary appliance. serves one or more fixture discharge pipes Fixture vent pipe (trap vent) A vent pipe that for any one floor. is connected to a fixture discharge pipe or Branch vent pipe A vent pipe that serves two the sanitary fixture itself. or more fixture vent pipes. Floor waste An outlet located at the low point Building has the meaning ascribed to it by of a graded floor or in a level floor designed to Amend 1 Jun 2007 Sections 8 and 9 of the Building Act 2004. receive accidental or intentional discharges. Cleaning eye A small diameter access point Floor waste pipe A pipe that receives the usually formed as part of a fitting or trap. discharge from a floor waste and that Combined waste pipe A discharge pipe discharges outside the building or to the foul which serves two or more waste pipes. water drainage or sanitary plumbing system. Developed length The total length along the Foul water The discharge from any sanitary centre line of a pipe including fittings and bends. fixture or sanitary appliance. Diameter (or bore) The nominal internal diameter. Foul water drainage system Drains, joints and fittings normally laid underground and used Discharge pipe Any pipe that is intended to specifically for the conveyance of water from convey discharge from sanitary fixtures or the plumbing system to an outfall. sanitary appliances. Graded A floor or pipework installed with slope Discharge stack A discharge pipe that has one or gradient. or more discharge pipe connections, and which is vented at one end via a discharge Gradient Inclination expressed as the ratio or Amend 10 stack vent. percentage of unit rise to horizontal distance. Nov 2023 Discharge stack vent A vent pipe connected Grease trap A device designed to intercept to the top of the discharge stack. grease in a foul water discharge. Discharge unit The unit of measure for the Gully trap A fitting designed to prevent foul air discharge (hydraulic load) in the plumbing escaping from the drainage system and used system, and is based on the rate, duration to receive the discharge from waste pipes. M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 2 November 2023 9  F O U L W AT E R D efinitions G13/V M1/V M2 & AS 1/AS2/AS 3 Inspection chamber A chamber with working Rodding point A removable cap at ground space at ground level through which the level through which access may be made for drain passes either as an open channel or as cleaning and inspecting the drainage system. a pipe incorporating an inspection point. Sanitary appliance An appliance which is Inspection point A removable cap at drain intended to be used for sanitation and level through which access may be made which is not a sanitary fixture. Included are for cleaning and inspecting the drainage machines for washing dishes and clothes. system. Sanitary fixture Any fixture which is intended Network utility operator means a person who— to be used for sanitation. COMMENT: a) undertakes or proposes to undertake Toilets, urinals, bidets, baths, showers, basins, sinks the distribution or transmission by pipeline Amend 9 and tubs are examples of common sanitary fixtures. Nov 2020 of natural or manufactured gas, petroleum, biofuel, or geothermal energy; or Sanitation The term used to describe the activities of washing and/or excretion carried b) operates or proposes to operate a out in a manner or condition, such that the network for the purpose of— effect on health is minimised, with regard to i) telecommunication as defined in dirt, contamination and infection. section 5 of the Telecommunications Sewer A drain that is under the control of, or Act 2001; or maintained by, a network utility operator. ii) radiocommunications as defined Soil fixture A sanitary fixture constructed to in section 2(1) of the receive solid and/or liquid excreted human Radiocommunications Act 1989; or waste. It includes bedpan disposal units, c) is an electricity operator or electricity slop sinks, urinals, water closet pans, and distributor as defined in section 2 of water-flushed sanitary towel disposal units. the Electricity Act 1992 for the purpose Surface water All naturally occurring water, of line function services as defined in other than sub-surface water, which results that section; or from rainfall on the site or water flowing d) undertakes or proposes to undertake onto the site, including that flowing from the distribution of water for supply a drain, stream, river, lake or sea. (including irrigation); or Vent pipe A pipe for the purpose of protecting e) undertakes or proposes to undertake water seals that at its upper end is either Amend 4 Oct 2011 a drainage or sewerage system. open to the atmosphere or fitted with an air admittance valve and that at its lower end is Outfall That part of the disposal system connected to a discharge pipe. receiving surface water or foul water from the drainage system. For foul water, the Waste pipe A discharge pipe that conveys the outfall may include a sewer or a septic tank. discharge from waste water fixtures to a For surface water, the outfall may include a gully trap. natural water course, kerb and channel, or Waste water fixture A sanitary fixture or soakage system. sanitary appliance used to receive wastes, and which is not a soil fixture. Plumbing system Pipes, joints and fittings, laid above ground and used for the Water seal The depth of water that can be conveyance of foul water to the foul water retained in a water trap. drain and includes vent pipes. Water trap A fitting designed to retain a depth Relief vent A vent pipe which is connected to of water that prevents foul air and gases a discharge stack below the lowest branch escaping from the plumbing system or foul connection and which connects at its upper water drainage system and entering a building. end to the discharge stack vent or terminates as an open vent. 10 5 November 2020 M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T  F O U L W AT E R Ve ri f i ca tio n Me th o d G1 3 /AS1 S A N I TA R Y P L U M B I N G Verification Method G13/VM1 Sanitary Plumbing 1.0 Sanitary Plumbing 1.0.1 A design method for conveying foul water from buildings, and for avoiding the likelihood of foul air entering buildings, may be verified as satisfying the relevant Performances of NZBC G13 if the method Amend 3 Sep 2010 complies with BS EN 12056.2. D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 3 0 S e p t e m b e r 2 010 11 12  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G Acceptable Solution G13/AS1 Sanitary Plumbing 1.0 Scope 2.0 Materials 1.0.1 This Acceptable Solution applies to 2.1 Pipes, traps and fittings above-ground non-pressure (gravity flow) 2.1.1 Materials for sanitary plumbing systems sanitary plumbing for buildings having 3 levels using gravity flow shall comply with Table 1. or less and includes all pipework for foul water within, or on the building, including any COMMENT: basements. Products for use in sanitary plumbing systems that have been certified and marked in accordance with the 1.0.2 The solution does not include: requirements of the Australian WaterMark Certification Scheme and listed on the WaterMark Product Database a) Specialised types of sanitary fixtures or may be deemed to meet the requirements of Paragraph sanitary appliances used within buildings such 2.1.1 for their intended purposes. Amend 10 Nov 2023 as hospitals, laboratories and factories, or b) The conveyance of industrial liquid wastes, 3.0 Water Traps chemical or toxic wastes and other wastes which cannot be discharged to a sewer 3.1 Water trap requirements without pretreatment. 3.1.1 Discharge points from sanitary fixtures 1.0.3 Protection of water seals and sanitary appliances shall have a water trap to prevent foul air from the plumbing system Water seals shall be protected from pressure entering the building. fluctuations within the sanitary pipework so as to prevent foul air and gases from entering the 3.1.2 Water traps shall be: building. The method described in this a) Removable, Acceptable Solution for protecting water seals b) Able to be dismantled, or is based on a fully vented plumbing system and generally requires each fixture discharge c) Fitted with a cleaning eye. pipe to be vented. COMMENT: COMMENT: Removable panels are not required for access to Individually venting each fixture discharge pipe provides bath traps. the greatest flexibility in the arrangement and lengths of discharge pipes. Material Standard Pipes and fittings Amends 3 and 9 Air admittance valves ASSE 1050 or ASSE 1051, BS EN 12380, AS/NZS 4936 Amend 10 Copper pipe NZS 3501, AS 1432 Nov 2023 Copper fittings AS 1589 PVC pipe and fittings AS/NZS 1260 Plastic fittings AS 2887 Amend 3 PE pipe and fittings AS/NZS 4401 Sep 2010 Elastomeric rings AS 1646 Polypropylene AS/NZS 7671 Stainless steel BS EN 1124 Parts 1 and 2 Amend 10 Nov 2023 Traps Plastic AS 2887 Copper AS 1589 M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 2 November 2023 13  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 3.2 Water trap dimensions 3.2.2 The diameter of the water trap shall be 3.2.1 Under normal operating conditions, not less than that given in Table 2. fixture traps shall retain a water seal depth of not less than 25 mm (see Figure 1). 3.3 Water trap location COMMENT: 3.3.1 A water trap shall: 1. The nominal depth of water seal is 75 + – 10 mm for a) Be located as close as possible to the waste water fixture traps. sanitary fixture or sanitary appliance it 2. The nominal depth of water seal is 50 + – 5 mm for soil serves, fixture traps. b) Have a discharge pipe with a developed 3. The system should be tested under load conditions to length not exceeding 1.2 m measured ensure that a 25 mm minimum water seal depth is between the water seal and either the not compromised. sanitary fixture outlet or the sanitary appliance discharge point, and c) Not be located in a different room to the sanitary fixture or sanitary appliance it serves. COMMENT: 1. Waste material may build up on the walls of discharge pipes and may cause offensive odours to enter the building through the fixture outlet. A short discharge pipe reduces the likelihood of this happening. 2. Traps may be located under the floor or in ceiling spaces of the floor below. 3.3.2 Multiple outlets A single water trap may serve any one of the following outlet combinations located within the same space (see Figure 2): a) One or two adjacent domestic kitchen sinks together with a dishwashing machine. b) One or two adjacent domestic kitchen sinks together with a waste disposal unit. c) One or two adjacent laundry tubs together with a clothes washing machine. d) Two adjacent basins, domestic kitchen sinks or laundry tubs. e) One or two adjacent domestic kitchen sinks, together with a waste disposal unit and a dishwashing machine when fitted with a 50 mm trap and discharge pipe. COMMENT: Commercial sinks – one water trap is not permitted to serve two adjacent commercial sinks, as a sink containing foul water may contaminate an adjacent sink being used for food preparation. 14 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G Sanitary fixture or appliance Discharge units Minimum trap and discharge pipe diameter (mm) Basin 1 32 Bath (with or without overhead shower) 4 40 Bathroom group (water closet pan, 6 (Note 1) bath and shower, basin, and bidet in one compartment) Bidet 1 32 Cleaner’s sink 1 40 Clothes washing machine (domestic) 5 40 Dishwashing machine (domestic) 3 40 Drinking fountain 1 25 Kitchen sink (commercial) 3 50 Kitchen sink (domestic, single or 3 40 double, with or without waste disposal unit) Laundry (single or double tub, 5 40 with or without a clothes washing machine) Shower 2 40 Urinal (1 or 2 stall) 1 per 600 mm length 50 Urinal (bowl type) 1 32 Urinal (3 or more stalls) 1 per 600 mm length 80 Water closet pan 4 80 Note: 1. For groups of fixtures, traps are sized for the individual fixtures. Discharge pipes for groups are sized in accordance with Paragraph 4.3.2. 3.4 Floor outlets b) Be trapped, charged to maintain the water 3.4.1 Floor waste outlets shall have a seal and discharge to the foul water removable grating that is flush with the floor. plumbing system in accordance with Paragraphs 4.5 and 5.0, or COMMENT: c) If its only purpose is to discharge accidental 1. The grating is to permit safe and easy movement of people using the space containing the floor outlet. overflows: 2. Floor wastes in this section are not intended to i) have no water trap, receive liquid or excreted human wastes. ii) discharge to the open air within the 3.4.2 The floor waste, and the water trap property boundary, if used, shall have a minimum diameter of iii) discharge to a safe location, and 40 mm. iv) be fitted with a means to prevent the 3.4.3 A floor waste shall: entry of birds and vermin. a) Be trapped, discharge 50 mm above the grating of a gully trap and be vented as shown in Figure 3, D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 15  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 16 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 17  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 Number of floor wastes Diameter of waste outlet Discharge stack size (mm) (mm) 1–3 40 40 4–6 40 50 1–3 50 50 4–6 50 80 3.4.4 Floor waste pipes may be combined All trap charging systems shall incorporate to form a floor waste stack and shall have a backflow prevention in accordance with diameter not less than that given in Table 3 G12/AS1. (see Figure 3). COMMENT: Individual floor waste pipes connected to a Backflow protection can be achieved by an appropriate floor waste stack need not be vented (see air gap or backflow prevention device. Figure 3). 3.4.5 Floor waste discharge stacks shall: 4.0 Discharge Pipes a) Be open vented, 4.1 Layout b) Be vented independently from any other 4.1.1 Discharge pipes shall follow the most sanitary plumbing system, and practicable route with the least number of c) Comply with the termination requirements bends. of Paragraph 5.7.4. COMMENT: 4.2 Access for cleaning Independent venting reduces the risk of foul air and 4.2.1 Access points shall be provided in gases entering the floor waste system. discharge pipes to allow the easy clearance of 3.4.6 Charging floor wastes blockages. The water seal of a trapped floor waste 4.2.2 Access points shall be provided at the discharging directly to the foul water plumbing following points: system shall be maintained by (see Figure 4): a) At the junction of a soil discharge pipe with a) A charge pipe of not less than 32 mm a discharge stack, diameter from a tap or a drain from a hot or b) Where a number of changes of direction cold water relief valve, which shall drain occur, over a tundish so that the air gap is c) In a discharge pipe where access to maintained, junctions or changes of direction are b) A mechanical trap priming device and restricted, and discharge pipe, d) At the base of any soil stack at the point of c) A tap for floor washing, located in the same connection to the drain. room and in close proximity to the floor COMMENT: waste. Proprietary fittings that provide access into the pipe In all cases the charge pipe shall have a should be used at these points. maximum length of 10 m. 18 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 19  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 4.3 Diameter 4.5.2 Water seal protection: Waste water 4.3.1 Fixture discharge pipes shall have fixture discharge pipes shall be vented to diameters of not less than those given in comply with Paragraph 5.0 and as required in Table 2 and shall not decrease in size in Table 5. the direction of flow. 4.6 Fixture discharge pipes serving soil 4.3.2 Where a discharge pipe receives the fixtures discharge from more than one fixture, the diameter of the discharge pipe shall be not 4.6.1 Fixture discharge pipes serving soil less than that required in Table 4 using: fixtures shall discharge either: a) The discharge unit loading to be conveyed, a) Directly to the drain, as shown in Figure calculated as the sum of the discharge unit 6(1), or loading given in Table 2, for all fixtures b) To a stack, as in Paragraph 4.7 and as served, and shown in Figures 7 and 8. ‑ b) The gradient of the discharge pipe. 4.6.2 Water seal protection: Soil fixture discharge pipes shall be vented to comply with 4.4 Gradient Paragraph 5.0 and as required in Table 5 (see Figure 6(2)). 4.4.1 The gradient of discharge pipes shall be not less than that required in Table 4 for the 4.6.3 Junctions in graded soil fixture branch relevant discharge unit loading. discharge pipes shall be installed so that the entry level of each branch connection is COMMENT: elevated at an incline of not less than 15° The minimum gradients specified are necessary to avoid Amend 10 above the horizontal (see G13/AS2 Figure 1(b)). Nov 2023 the risk of blockage. 4.5 Fixture discharge pipes serving waste water fixtures 4.5.1 Waste water fixture discharge pipes shall discharge either to: a) A gully trap, in accordance with Figure 5 of G13/AS1 and Figure 3 of G13/AS2, or b) A discharge stack as in Paragraph 4.7 and Figures 7 and 8. Diameter Maximum Vertical Graded discharge pipes (mm) discharge stack from any (Note 1) Minimum gradient one floor 1:20 1:30 1:40 1:50 1:60 32 1 1 1 40 2 6 6 5 4 50 5 15 15 10 8 65 6 18 51 29 21 80 13 40 65 39 27 20 16 100 65 195 376 248 182 142 115 Note: Shaded area = not permitted 1. Total loading at the base of the discharge stack. 20 2 November 2023 M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 21  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 22 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 23  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 4.7 Discharge stacks b) For vertical stacks, be extended up past the 4.7.1 Discharge stacks shall: top-most branch connection to form a discharge stack vent (see Paragraph 5.0 and a) Have a diameter of not less than that given Figure 7). in Table 4 using: c) For graded discharge stacks, have a i) the discharge unit loading to be discharge stack vent connected to the conveyed, calculated as the sum of the graded section of the stack downstream discharge unit loadings required in Table 2 of the highest fixture, in accordance with for all fixtures served, and Paragraph 5.0 and Figure 8. ii) the gradient of the discharge stack. 24 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G 4.7.2 Where discharge pipe connections to 5.1.2 Vent pipes that serve fixtures that vertical discharge stacks: discharge to a gully trap or grease trap shall be a) Are near the base of a discharge stack, they vented independently of any vent pipe system shall not be connected to the discharge connected directly to the foul water drainage stack or drain within the positive pressure system. zone as shown in Figure 7. COMMENT: COMMENT: An independent vent pipe system for fixtures discharging to a gully trap is necessary to avoid the risk Whenever a discharge stack incorporates a bend greater of sewer gases escaping through any waste pipes than 45°, a hydraulic jump may occur in the horizontal discharging to a gully trap. pipe downstream of the bend. The hydraulic jump can cause very high positive pressures in the pipe near the bend. If a branch pipe is connected to the discharge 5.2 Vent pipes stack in this zone, these high pressures may blow out water seals connected to that branch pipe. 5.2.1 Vent pipes shall be one of the following types: b) Consist of two branches entering the discharge stack at the same level, they shall a) A vertical or graded fixture vent pipe have a double Y-junction with either: terminating in accordance with Paragraph 5.7.1 or 5.8.1 (see Figure 10 (a)), or i) sweep entries, or b) An ascending graded or vertical fixture vent ii) entries with an included angle of 90° pipe to connect to: (see Figure 9 (b)). i) a branch vent pipe, as shown in c) Are at different levels, they shall not be Figure 10 (b), connected to the discharge stack within the restricted entry zones shown in Figure 9 (a), ii) a discharge stack vent as shown in unless the connection method is in Figures 7, 8 and 10 (b), or accordance with Figures 9 (b) and (c). iii) a relief vent, as shown in Figure 7. 4.7.3 Where discharge pipe connections are to The connection shall be made at a height of graded discharge stacks they shall not enter at not less than 50 mm above the overflow level opposite positions and if they are near bends of the sanitary fixture it serves. they shall not be made within 450 mm of any bend (see Figure 8). 5.3 Diameter of vent pipes 4.7.4 Junctions in graded 100 mm diameter 5.3.1 Fixture vent pipes, branch vent pipes, discharge stacks shall be installed so that discharge stack vents and relief vents shall the entry level of each branch connection have a diameter of no less than that given in is elevated at an incline of not less than Table 6. 15° above the horizontal (see G13/AS2 Figure 1(b)). Amend 10 Nov 2023 4.7.5 The change of direction at the base of any vertical section in a discharge stack shall incorporate: a) Two nominal 45° bends, or b) One nominal 45° bend and a Y-junction. 5.0 Venting 5.1 Venting required 5.1.1 Discharge pipes shall be vented where required by Table 5. M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 2 November 2023 25  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 Stacks Stack vent: All stacks discharging to another stack or to a drain require an open vent, sized in accordance with Table 6. Venting with an air admittance valve is permitted only on second and subsequent stacks as at least one open vent (the stack vent, if acting as main drain vent) is required to ventilate the drain. Relief vent: All stacks that receive discharges from 3 floor levels shall be vented with a relief vent sized in accordance with Table 6. Relief vents shall be open vented. Fixtures connected to a stack All connections to a stack, except the highest connection, require venting by either an open vent, or an air admittance valve, sized in accordance with Table 6. Highest fixture connected to a stack The individual highest connection to a stack requires venting by either an open vent, or an air admittance valve, sized in accordance with Table 6, if the discharge pipe is longer than: – 6 m for 100 mm pipe, – 1.5 m for 80 mm pipe, and – 3.5 m for 65 to 32 mm pipes. Soil fixtures connected to an unvented branch drain All soil fixtures connected to an unvented branch drain require venting by either an open vent, or an air admittance valve, sized in accordance with Table 6. Soil fixtures connected to a vented drain with a gradient of less then 1:60 All soil fixtures connected to a vented drain, where the branch and the vented drain are at a gradient of less than 1:60, require venting by either an open vent, or an air admittance valve sized in accordance with Table 6. Individual soil fixtures connected to a vented drain with a gradient of 1:60 or steeper Individual soil fixtures connected to a vented drain, where the branch and the vented drain are at a gradient of 1:60 or steeper, require venting by either an open vent, or an air admittance valve, sized in accordance with Table 6, if the discharge pipe is longer than: – 6 m for 100 mm pipe, or includes a vertical drop greater than 2 m, and – 1.5 m for 80 mm pipe diameters. Fixtures discharging to a gully trap 1. Fixtures connected to a combined waste pipe require venting by either an open vent, or an air admittance valve, sized in accordance with Table 6. 2. Individual fixture discharge pipes over 3.5 m in length require venting by either an open vent, or an air admittance valve, sized in accordance with Table 6. 3. Where any 32 mm discharge pipe has a vertical drop of greater than 1.5 m it shall be vented with a 32 mm vent pipe or an air admittance valve. Venting of main drains Main drains discharging to the sewer or to an on-site disposal system are required to be vented with a minimum 80 mm open vent. Venting of branch drains Branch drains connected to a vented drain­that exceed 10 m in length require venting with an open vent, sized in accordance with Table 6. 26 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 27  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 28 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G For fixture vent pipes Diameter of fixture Minimum diameter of discharge pipe fixture vent pipe (mm) (mm) 32 32 40 32 50 40 65 40 80 40 100 40 For branch vent, branch drain vent, relief vent (see Note) and discharge stack vent pipes Maximum discharge Minimum diameter of units connected to the open vent pipe discharge pipe (mm) Up to 15 40 16 to 65 50 66 to 376 65 More than 376 80 For main drain vents Maximum discharge Minimum diameter of units connected to the open vent pipe discharge pipe (mm) Not applicable 80 Note: Relief vent sizes are acceptable for a maximum developed length of 12 m. 5.4 Gradient of vent pipes ii) to the discharge pipe within 1.5 m of 5.4.1 Fixture vent pipes and branch vent pipes the crown of the trap, and not less than shall extend upwards from the point of 300 mm above any bend at the base of connection to the fixture discharge pipe to the a vertical drop (see Figure 6(2)). open atmosphere, or to an air admittance b) If serving a basin or bidet: at a point valve, with a gradient of not less than 1:80. between 75 mm and either (see Figure 11 (b)): 5.5 Connection of vents to fixture i) 600 mm from the crown of the water discharge pipes trap, or 5.5.1 The fixture vent pipe, when required by ii) before the first bend in the fixture Table 5 for fixtures discharging to a gully trap, discharge pipe. shall connect to the waste pipe at a point c) If serving other fixture discharge pipes: at a between 75 mm and 3.5 m from the crown of point between 75 mm and 1.5 m from the the water trap, as shown in Figure 11 (a). crown of the water trap, provided that the 5.5.2 The fixture vent pipe, when required by connection is not less than 300 mm above Table 5 for fixtures discharging to a stack or any bend at the base of a vertical drop within directly to the drainage system, shall connect: the fixture discharge pipe (see Figure 11 (b)). a) If serving a WC pan: i) to the vent horn of the pan, or D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G 1 O c t o b e r 2 0 01 29  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 30 1 O c t o b e r 2 0 01 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G 5.6 Discharge stack and relief vents a) Ground level – 3.0 m above, 5.6.1 The discharge stack vent, if also acting as b) Windows and other openings – 600 mm a drain vent pipe shall have a diameter of not above, and 3.0 m below and horizontally, less than 80 mm. Where not acting as a drain c) Roofs – 150 mm above, vent the discharge stack vent pipe shall have a d) Decking having pedestrian access – 3.0 m diameter of not less than that required in Table above, below and horizontally, 6. e) Eaves or parapets – 600 mm above, below 5.6.2 Every discharge stack serving sanitary and horizontally, and fixtures or sanitary appliances from 3 floors within a building shall include a relief vent pipe f) Air intakes – 5.0 m in any direction. as shown in Figure 7. COMMENT: 5.6.3 Relief vent pipes shall: These requirements reduce the likelihood of foul air from the foul water drainage system entering the building. a) Connect to the bottom of the discharge stack at no less than 300 mm below the 5.7.4 Fixture vent pipes serving waste pipes lowest discharge pipe served, and at an discharging to a gully trap shall: angle of 45°, as shown in Figure 7, a) Terminate outside the building and be not b) Be extended upwards at a gradient of no less than 900 mm from any opening to the less than 1:80 to connect to the discharge building, and stack vent, as shown in Figure 7, or extend b) Be vented to the atmosphere independently separately to the atmosphere as an open of any vent pipe system connected directly vent, and to the foul water drainage system. c) Have a diameter of no less than that given COMMENT: in Table 6. 1. The location of the outlet of the vent pipe serving a waste pipe is less restrictive than the requirements for 5.7 Termination of open vent pipes vent pipes serving discharge pipes connected directly to the drain. This is permitted because a waste pipe 5.7.1 Open vent pipes shall terminate outside is not connected directly to the foul water drainage the building in accordance with Paragraphs system, and hence a source of foul air. 5.7.2 and 5.7.3 or 5.7.4. 2. An independent vent pipe system for waste pipes is needed to avoid the risk of sewer gases escaping 5.7.2 Vent pipes shall terminate outside the through a waste pipe to a gully trap. building and: a) Be at a height of not less than 50 mm 5.8 Air admittance valves above the overflow level of the highest sanitary fixture they serve, and 5.8.1 General Air admittance valves may be used as venting COMMENT: The height of 50 mm above the overflow level is to where specified in accordance with Table 5. ensure that the vent pipe does not convey foul water in 5.8.2 Air admittance valves shall be the event of the discharge pipe becoming blocked. manufactured to ASSE 1050, ASSE 1051, Amends b) Incorporate a means to prevent the entry of BS EN 12380 or AS/NZS 4936. 6 and 9 birds and vermin and shall have an 5.8.3 Size of air admittance valves open area not less than 80% of the The air admittance valve shall have a diameter Amend 6 cross-sectional area of the vent pipe they Jan 2017 no less than that given in Table 6, and be no serve. smaller in diameter than the vent pipe that 5.7.3 Open vent pipes serving discharge pipes it serves. directly connected to the foul water drainage Air admittance valves that form an integral part system shall terminate no closer to building of a fixture trap shall only be used as a trap elements than (see Figure 12): vent. M I N I S T RY O F B U S I N E S S , I N N O VAT I O N A N D E M P L OY M E N T 5 November 2020 31  F O U L W AT E R S A N I TA R Y P L U M B I N G Acceptable S olution G13/AS1 5.8.4 Location COMMENT: A significant amount of ventilating pipework and roof Air admittance valves shall be installed in an penetrations may be avoided with the use of air upright (vertical) position at least 100 mm admittance valves. However the pipework sizing, above the weir of the fixture trap and in a whether for individual fixture vents or branch vents, location (see Figure 10 (c)): should follow the requirements of this Acceptable Solution. Air admittance valves are intended for a) Accessible for maintenance and inspection, anti-siphon situations and may not protect the water seals of traps in positive pressure situations. b) Where the valve is unlikely to become frozen, 6.0 Installation c) Protected from likely damage, and d) Where adequate air can enter the valve. 6.1 Jointing methods Ventilated openings shall be provided for air 6.1.1 Jointing methods for PVC-U pipe shall Amend 3 admittance valves installed within a wall comply with AS/NZS 2032. Sep 2010 space. The free area of the openings shall be not less than 1.5 times that of the vent pipe. 32 3 0 S e p t e m b e r 2 010 D E PA R T M E N T O F B U I L D I N G A N D H O U S I N G  F O U L W AT E R Ac c e p ta b le So lu tio n G1 3 /AS1 S A N I TA R Y P L U M B I N G 6.2 Pipe supports 6.4 Fire separation 6.2.1 Pipes shall be supported at centres not 6.4.1 Fire stopping shall be fitted to pipes exceeding those in Table 7. passing through fire separations in accordance Amends Amend 3 6.2.2 For PVC-U pipes carrying discharges of with C/AS2 Paragraph 4.4. 6 and 8 Sep 2010 greater than 60°C, support for the pipe shall be in accordance with Paragraph 6.3.2 of 7.0 Watertightness Amend 3 Sep 2010 AS/NZS 2032. 7.1 Test methods COMMENT: