Mechanical Services Standard Specification Compressed Air Systems. May For ROYAL HOLLOWAY UNIVERSITY OF LONDON

Transcription

1 Mechanical Services Standard Specification Compressed Air Systems May 2010 For ROYAL HOLLOWAY UNIVERSITY OF LONDON

2 Prepared For The Estates Division By: Hulley & Kirkwood Consulting Engineers Ltd Castle House, Horizon Centre Upper High Street Epsom Surrey KT17 4RS (t): (f): (e): (w): Author: Checked: Approved: David Bantock/Andrew Wakelam Wayne Shipley Wayne Shipley Page 2

3 AMENDMENTS Author Date/Rev Description D Bantock / A Wakelam January 2010 Draft Issue W Shipley May 2010 Comments incorporated after meeting with RHUL Page 3

4 Index: 5.1 INTRODUCTION PIPEWORK General Pipework Preparation Fittings Dezincification Inaccessible Services Minimum Clearances Pipes Passing Through Walls Sleeve / Pipe Clearance Fire Rated Sleeves Wall Clearance Supports Suspended Pipework Wall Mounted Pipework Spacing Expansion Devices Electrical Continuity (Expansion Devices) Care and Storage of Pipework Care of Pipes Gaskets and Fittings Open Ends Connectors Plant Items Draining, Venting and Isolating Requirements Drain Cocks Pipework and Fittings Steel Pipework and Joints Steel Fittings Copper Pipework Joints and Fittings Plastic Pipework and Fittings Compressed Air System Components...12 Page 4

5 5.1 INTRODUCTION This specification covers the requirements for providing compressed air pipework systems associated with general usage. It does not include specialist application associated with medical research, etc. Specialist installers fully conversant and experienced with medical gas systems would normally be engaged to undertake this work. Installers undertaking compressed air systems should be fully qualified and experienced in the supply, installation and commissioning of these systems at the various working pressures. The use and application of material covered in this specification shall be in accordance with the system working pressure and application as identified by Royal Holloway University of London. ALL WORKS ARE TO BE INSPECTED BY THE TENDERING CONTRACTOR PRIOR TO PRICING HEALTH AND SAFETY STATEMENT Health and Safety precautions are required to be taken during the process of undertaking works within buildings cannot be underestimated. Reference shall be made to Royal Holloway University Health and Safety Policy and Contractors Guidance documents available from Royal Holloway University of London Estates Office. The Health and Safety Executive (HSE) publish a series of guidance documents regarding all many different methods of protecting the workforce and people in general when working with hazardous chemicals (COSH) and undertaking potential dangerous work activities. Installers engaged in any work shall be registered with the Construction Skills Certificate Scheme (CSCS) and be in possession of a valid skills card. Page 5

6 5.2 PIPEWORK General The Installers shall allow for installing services in a coordinated manner setting round obstructions to circumvent site difficulties which may not be obvious from the drawings as applicable issued with the works package. All pipework unless specifically identified shall be concealed and installed within false ceilings and architecturally designed service ducts. Pipework in visually exposed conditions shall be installed to have the neatest practicable finish. Pipes generally shall follow the contour of walls etc. Vertical pipes shall be plumb, without off-sets and be set close to local projections in order to follow their lines. No joints shall be made inside the thickness of walls, partitions, floors or ceilings. No pipework shall be concealed withing walls or buried in floors Pipework Preparation Dependent upon the materials being used pipework shall be prepared in strict accordance with the manufacturers recommendations with any lubrication liquids being cleaned off to the manufacturers standards Fittings Pipe fittings shall be installed in such a manner that air or condensate cannot be trapped and pipes can be drained. Care shall be taken to avoid the defacing of fittings. Spanners of the correct size shall be used on all hexagons. Fittings shall be rejected if badly marked and the Installer shall replace such at his own expense Dezincification All fittings, valves, cocks, etc. except where otherwise specified (e.g. cast iron), shall be manufactured from copper, gunmetal, bronze or other agreed materials to prevent dezincification Inaccessible Services All steel pipework runs located within inaccessible areas (e.g. above plaster ceilings, obstructed by ductwork etc.), shall be welded, and all copper pipework shall be brazed. Screwed, compression and flanged joints shall not be permitted in inaccessible locations. The emphasis shall be to avoid joints wherever possible. All pipework tube in contact with the soil or building fabric shall be protected by being twice wrapped in Denso tape or similar and equally agreed. Page 6

7 Minimum Clearances Pipes shall be installed so as to give the following minimum clearances between the pipe and adjacent surfaces, as follows; Walls 25mm Ceilings 100mm Finished Floors 165mm Adjacent Pipes 150mm Pipes to adjacent conduit or trunking 100mm Pipes adjacent to electrical cables not in conduit or trunking 150mm Pipes Passing Through Walls All pipes passing through walls, floor, ceilings, partitions etc. shall be inserted through sleeves of similar material to the pipe provided as part of the installation works. In exposed to view areas eschutcheon plates shall be provided to conceal the sleeves Sleeve / Pipe Clearance Sleeves shall be free from internal burrs and shall have an internal diameter sufficient to allow the pipe to be fixed clear of the sleeve at all points, with at least 3mm gap between sleeve and pipe at all points Fire Rated Sleeves Pipes passing through internal walls, floors or partitions, which are fire barriers, shall have a fire sleeve that complies with the current Building Regulations and tested to BS 476 for a minimum of 2 hours Wall Clearance Sleeves shall be of sufficient length to clear the face of finished wall or ceiling by at least 3mm Supports The Installer shall supply, fix and accurately set out all supports, bolts etc. necessary to suit the runs of pipework. The supports shall be suitable for the duty required and the areas in which the pipe is run. The type of support shall be dependant on location, type and size of the pipework Suspended Pipework Brackets shall consist of ball hanger assemblies comprising split pipe gland or one piece pipe clip, drop rod, locknut and male ball hanger. Page 7

8 For copper pipework, brackets, clips and glands shall be manufactured from gunmetal or brass, for mild steel and galvanised steel pipework, they shall be of a similar material to the pipe. For plastic pipework the selected manufacturers products and recommendations or equal shall be applied. The Installer shall make his own fixings to the structure and prior to any works being undertaken the Installer shall agree the method of fixing to comply with the structural limitations and the requirements of Royal Holloway University of London Wall Mounted Pipework Brackets for vertical pipework shall be of the rigid type to guide the pipework and shall comprise a two piece pipe gland, locknut and screwed rod. For copper pipework, brackets, clips and glands shall be manufactured from gunmetal or brass, for mild steel and galvanised steel pipework, they shall be of a similar material to the pipe. Supports for pipework to be chrome plated shall be of similar finish but the support assembly shall comprise split pipe ring, extended nipple and back plate securely fixed to the structure. All brackets and hangers shall be installed with special attention to freedom for lengthways expansion, either in horizontal or vertical plane and to levels for air elimination and drainage. Supports for rise and drop pipes shall be arranged to allow freedom for expansion movement or horizontal runs. Pipes shall be adequately supported at bends, tees and where changes of direction occur. Vertical risers shall be supported at the base to withstand total weight. Branches from risers shall not be used as means of support for the riser. Valves 76mm and above shall be individually supported. Where it is not practicable to use standard type brackets the Contractor shall supply and fix suitable purpose made supports to suit the position. All pipelines shall be separately supported and pipes slung from other pipes shall not be allowed. "Double" type hangers shall not be used due to the differential in expansion and contraction of the two pipelines and the difficulty of doing work on one pipeline without disturbing the other. All necessary metal supports, tees, angle or channel sections, screws, bolts etc. shall be provided and fixed by the Installer who shall be responsible for the accurate setting of same. For plastic pipework the Installer shall follow the manufacturers materials recommendations for compatibility with the pipework being used. Page 8

9 Spacing The spacings between pipe supports shall not exceed the following values: Note: Additional bracketry should also be considered where directional changes occur. Pipe Material Mild Steel Pipe Nominal Bore Intervals for Horizontal Runs mm m m Intervals for Vertical Runs Light Gauge Copper and above Plastic 16mm 20mm 25mm 32mm 40mm 50mm 67mm 75mm 90mm The support distances shall also be subject to the selected manufacturers recommendations and materials used. Horizontal and vertical pipe fixings and supports shall be arranged at intervals not greater than those shown in the above table for plastic pipework. They shall also be subject to the selected manufacturers recommendations and materials used Expansion Devices The Installer shall be responsible for the design of expansion systems that may be required. For plastic pipework the selected pipework manufacturers should provide all relevant technical data. Expansion of pipework where possible shall be taken up by natural off-sets and changes of direction of pipe runs. Where this cannot be achieved, the Installer shall provide expansion loops, angular expansion compensators, and axial expansion compensators to suit. Page 9

10 Adequate provision shall also be made at all connections to equipment and appliances to avoid stress due to contraction and expansion Electrical Continuity (Expansion Devices) The pipework installations shall be electrically continuous up to and including the plant and equipment. The Installer shall provide and install earth bonding across all flexible joints including those on plant and equipment as necessary. If a mixture of steel, copper and plastic pipework is installed earth bonding of plant and all components shall be provided. 5. Care and Storage of Pipework It is imperative that a high standard of cleanliness is maintained to a standard in order that the cleanliness test as described in ASTM B Clause 12 can be maintained. The Installer shall at all times, using the accepted correct lifting tackle, take great care in offloading and handling pipes and fittings of all types so as to avoid damage to the material and any protective coatings or coverings. Suitable storage areas on site shall be agreed with the client and proper supports to carry pipework clear of the ground shall be used, particularly in damp areas and outdoors. The Installer shall provide suitable protection and/or covers for pipes stored outdoors in order to protect them from the weather and in the case of plastic pipework from solar degradation. Royal Holloway University of London shall reserve the right to reject or have rectified at the Installer's expense any damaged materials Care of Pipes Gaskets and Fittings The Installer shall at all times observe the installation and storage procedure as recommended by the Manufacturers. Gaskets shall be carefully stored to prevent damage. RHUL reserve the right to require any damaged materials to be removed from site Open Ends Care shall be exercised during the erection of pipework to ensure that foreign matter is not allowed to remain on or enter the pipes. When any portion of the installation is left open for any purpose whatsoever, the open end shall be temporarily sealed with purpose made plugs or blanking caps manufactured from sound wooden, metal or plastic materials. Rags, paper or similar substances shall not be used under any circumstances. A valve fitted at the end of a disconnected pipe shall not be considered satisfactory to prevent the ingress of foreign matter. All open ended pipework shall be permanently capped upon completion. Failure to comply with this instruction shall mean that Royal Holloway University of London shall have the right to instruct the Installer that pipework is left uncovered shall be dismantled and the pipework blown-through and/or cleaned at no expense to Royal Holloway University of London. Page 10

11 5.2.5 Connectors Unless otherwise specified, pipelines up to and including 50mm connectors shall be unions, or couplings (Cu) of materials suitable for the service. In pipelines 65mm, 67mm(Cu) and above, connectors shall consist of flanges made of an appropriate material and specification to BS Standards. Sockets and backnuts shall not be used under any circumstances Plant Items All connections to plant and equipment requiring internal inspection and maintenance shall be made using compatible coupling/flanges and positioned as to enable such inspections and maintenance readily and conveniently to be undertaken with the minimum disturbance of pipework and thermal insulation Draining, Venting and Isolating Requirements All pipework shall be installed with sufficient gradient to ensure adequate venting and draining. The Installer shall be responsible for providing such draining and air release arrangements in the form of drain cocks or air vents, type as are specified and as are required to ensure that all sections and subsidiary sections of the installation can be completely drained. Fittings for draining and venting shall be suitable for the working pressure of the systems to which they are connected Drain Cocks Drain cocks shall be positioned as necessary to completely drain the installation and sections as required during operation. Drain cocks installed above floor level shall be fixed as unobtrusively as possible. Drain cocks shall be finished to match the pipework to which they are connected Pipework and Fittings The section of pipework and fittings for extensions or modifications to existing systems shall generally be of the same materials and generally traditional metal pipework. Where the Installer wishes to offer a different material, agreement shall be obtained from Royal Holloway University of London. All jointing methods and compounds shall be fully compatible with the materials being used. Completely new systems shall be reviewed for the best choice of materials, be compatible with the building usage, and system operating requirements. The materials currently available include steel, copper and plastic selected to suit the operating temperatures, pressures and application. Jointing methods include, screwed, welded, grooved, press fit, solvent welded, fusion welded, soldered, brazed and compression. Page 11

12 Steel Pipework and Joints Steel pipework and joints shall be mild steel galvanised or black medium weight or heavy weight manufactured in accordance with BS EN 10255: Joints shall be screwed or welded up to and including 50mm dia. Above this pipework shall be welded with flanged joints to be provided in accordance with BS EN Bolting of steel flanges shall be in accordance with BS EN Steel Fittings Steel fittings shall be in accordance with BS :2000 and 1256:2000 for malleable cast iron and copper alloy. Steel welded fittings shall be in accordance with BS EN :1999. Threaded fittings shall also be in accordance with BS Copper Pipework Joints and Fittings Copper pipework shall be light gauge in accordance with BS EN The following fittings and jointing methods may be applied to suit the application. (a) Capillary soldered fittings to BS EN 1254 Part 1 (b) Compression fittings to BS EN 1254 Part 2 (c) Push fit fittings (copper and plastic) to BS EN 1057 Suitable manufacturers shall be as Pegler/Yorkshire range, including Tectite, Kuterlite, Prestex and XPress Plastic Pipework and Fittings Durapipe manufacture Air-Line Xtra which is a specially formulated blend of ABS as is suitable for a continuous operation at 12.5 bar at 20 o C with a 30 year design life. Durapipe provide all fittings and valves and if used subject to agreement by Royal Holloway University of London, installation shall be carried out in strict adherence to the manufacturers instruction. The size range is from 16mm to 110mm. Alternative manufacturers may be considered but shall be equal and agreed to the satisfaction of Royal Holloway University of London Compressed Air System Components This section of the specification provides guidance as to the type and quality of components that would be acceptable to Royal Holloway University of London for use on compressed air systems. Spirax Sarco Ltd are a major manufacturer and specialist for compressed air components and the following products are available for selection and use on Royal Holloway University of London projects as required. Page 12

13 a) Spirax - Monnier Ultra Clean Compressed Air Filters b) Spirax - Monnier Compressed Air Regulators c) Spirax - Monnier Air Lubricants d) Spirax - Monnier Compressed Air Filter/Regulators e) Spirax - Airodyn Compressed Air Drain Trap f) Spirax - Air and Gas Trap g) Spirax Dri-line MK2 Compressed Air Drain Trap h) Spirax - Monnier Automatic Drain Valve i) Spirax - Monnier Venting and Non-Venting Ball Valve Page 13