B9.11 PIPEWORK LAYOUT

The Drawings indicate the size and general layout of the required pipework.

The exact position may not be indicated on the Drawings as for the purpose of clarity, they are generally shown as separately spaced out from one another as if they were at the same plan level. The A/C Contractor shall accurately set out the various pipelines in the Installations in compliance with the provisions of Clauses A3.16 and A4.3 of this General Specification.

B9.12 PIPEWORK SUPPORTS, EXPANSION JOINTS AND ANCHOR POINTS B9.12.1 Where the Employer’s Guide Drawings & Details for pipework supports and brackets, expansion joints and anchor points are issued with the Contract or have previously been issued to approved

contractors for general application on the Employer’s projects, these standard details shall be followed "in-principle" but adjusted as to the detail in order to suit the particular circumstances. Such adjustments shall be indicated on the A/C Contractor’s own Installation/Shop Drawing and loading calculation Submissions and be approved by the Architect before work commences.

B9.12.2 Pipework shall be supported so as to permit free movement due to expansion and contraction. Pipework supports shall be installed as near as practicably possible to joints and changes in direction. Each support shall take its due proportion of the load. The spacing of the supports shall not exceed the centres given in Tables B9.17-(1), B9.17-(2) and B9.17-(3) under Clause B9.17. Where there are two or more pipes, the spacing shall be based on the centres required by the smallest bore pipework.

B9.12.3 Vertical rising pipework shall be supported at the base or, as indicated, to withstand the total weight of the riser. Branches from risers shall not be used as a means of support for the riser. If such base has to be rested on an intermediate floor slab, the A/C Contractor must draw particular attention to the Architect for structural reinforcement to the floor slab and also allow for additional treatment to the base as required by the Architect.

B9.12.4 Where pipework up to 50 mm size is fixed to solid wall, brackets may be of the screw-on or long shank built-in type in case the walls are plastered, only the long shank built-in type shall be used. For fixing to woodwork and lightweight partitions or walls, brackets shall be of the screw-on pattern of adjustable two-piece type. Brackets for mild steel and plastic pipework shall be mild steel or malleable iron;

brackets for copper pipework shall be brass or gunmetal. The upper half of the pipe clip shall be detachable without disturbing the fixing.

B9.12.5 Brackets screwed to walls shall be secured by expanding plugs. Other purpose designed fixing devices or softwood plugs will not be permitted.

B9.12.6 Pipework of 65 mm size and larger, subjected to expansion and contraction and hung from supports shall be suspended on swivel hangers unless otherwise agreed by the Architect.

B9.12.7 Unless otherwise specified, hangers for horizontal pipework at high level shall be supported from galvanized mild steel angle or channel sections or approved proprietary devices supplied by the A/C Contractor, suitable for building-in or otherwise securing to the structure by the Building Contractor. Adjustable mild steel hangers shall be used. Pipe rings shall be of malleable cast iron or fabricated steel, made in halves and secured by bolts or screws. Alternatively, malleable iron hinged pipe rings may be used. Calliper type hooks will not be permitted.

B9.12.8 Where pipework is fitted in service duct or trenches or where it is of 65 mm size or greater and supported from walls, the design of the pipe supports, guides and anchors shall be in accordance with the Drawings. Otherwise, the A/C Contractor shall submit details and proposal to the Architect for approval. Where roller supports are required, they shall be of an approved type. The performed insulation shall be kept free of the rolling surface. Load-bearing insulation at supports, where required, shall be fitted by the A/C Contractor at the time of erecting the pipework.

B9.12.9 For copper pipework, the anchors shall be provided by wide copper straps secured to the pipework in such a manner that the pipe is not damaged.

B9.12.10 The A/C Contractor shall supply, and fix in position ready for building-in, all cleats, brackets and steelwork required for anchor points. Anchor steelwork secured to the bottoms of ducts or trenches shall be coated with hot-poured bitumen to inhibit future corrosion.

B9.12.11 Supports for plastics pipework may be of any approved pattern that prevents free axial movement of pipe at all temperatures and have radial edges to prevent cutting into the pipe. The entire bearing surface must be sufficiently wide to prevent indentation.

Heavy "in-line" equipment must be supported independently. Valves and meters must also be supported independently, where necessary.

Supports for pipes carrying water at a maximum temperature of 15^oC and covered with lightweight insulation shall be spaced in accordance with Table B9.17-(3) under Clause B9.17. Alternatively, the pipework may be continuously supported, provided that the thermal insulation covering the pipework is sufficiently rigid to ensure that no compression or deformation of the insulation occurs.

B9.12.12 Provision for movement due to expansion and contraction shall be generally as indicated and/or shall be by changes in direction of the pipework, by loops or by other approved expansion devices.

B9.12.13 Supports and guides shall be arranged to ensure that all movement is taken up by the change in direction of the pipework or by the loop or device.

B9.12.14 The spacing of supports for steel, copper and plastic pipework shall be in accordance with Tables B9.17-(1), B9.17-(2) and B9.17-(3) under Clause B9.17.

B9.12.15 Cold bridge should be prevented between the insulated pipework and the associated hangers and pipework supports.

B9.12.16 All metal mounting and fixing brackets for water pipework shall be pre-fabricated off-site.