Pipe
Description
Work of this Section shall conform to the requirements of the Air Conditioning Contractor Documents.
Work Included
- Air Vents & Drains
- Relief Valves
- Strainers
- Pressure Gauge
- Thermometers
- Anti-Vibration Coupling
- Drain Corks
- Chilled Water Expansion Tank
Submittals
Submit manufacturer’s latest published data indicating rating data, catalogue, model numbers, dimensional information, and pressure drops.
Submit shop drawings prior to manufacturer. Do not proceed with fabrication of equipment until fully approved shop drawings have been returned.
Comply with all governing local codes and all regulations of the Department of Occupational Safety and Health.
Comply with the applicable requirements of ASME, ANSI, U.L., ASTM and IEC Regulations.
Piping Design
Air Vents and Drains
Wherever required for air venting, air bottles and cocks shall be provided. The bottles shall be of the same material and dia. as the pipes to which they are fitted up to and including 40mm diameter, for pipes above this size 40 mm diameter bottles approximately 450 mm long shall be used. At the top of the bottle a taper reducing fitting shall be installed with 12 mm vent pipe and air cock fitted at low level.
Automatic air vents shall be provided as necessary and shall be complete with isolating cock, and tail pipe arranged for visible discharge to the nearest suitable floor drain.
All portions of equipment and drip tray, pump wells etc. in which water may collect shall be drained to waste with copper drains. Drains shall be connected to equipment with unions to facilities cleaning and removal.
Drain Cocks
Gunmetal drain cocks shall be provided as necessary to ensure that all sections of the pipe work and plant can be effectively drained. The sizes of drain cocks shall be as follow:
Tank, Plant and pipes above 150 mm diameter not less than 25 mm diameter.
Pipes 75 mm to 125 mm diameter 20 mm diameter.
Pipes up to 65 mm diameter shall be complete with hose-unions for draining down.
Drain cocks of 12 mm diameter shall be complete with hose-unions for draining down.
Relief Valves
Relief and safety valves where fitted to pipe work shall be of the “Enclosed Spring Loaded” gunmetal type with outlet pipes terminating 6’ above floor level.
Strainers
In line Y type strainers shall be provided where shown on the drawings and as recommended by the pumps manufacturers. They shall be of the screwed gunmetal type up to and including 50 mm dia. Sizes 65 mm dia. and above shall be of the cast iron type and flanged.
Pressure Gauges
Where shown on the accompanying drawings 150 mm dia. brass cased pressure gauges shall be supplied and fitted. They shall be designed for pipe mounting and be calibrated in PSI and kPa. All pressure gauges shall be provided with suitable gauge cocks. The pressure gauge shall have accuracy of ± 3% or better. Provide valid calibration certificate for all gauges.
Thermometers
Where shown on the accompanying drawings suitable 150 mm brass cased red alcohol thermometers shall be supplied and fitted. The thermometers shall be designed for pipe mounting and complete with pipe well. Calibration shall be in deg F and deg C.
Anti-Vibration Coupling
Piping connections to all pumps, refrigerant condensers, evaporators, cooling towers, air handling apparatus and all equipment shall be by means of wire or fabric reinforced moulded high pressure convoluted rubber connectors. The fittings shall have integral rubber flanges and be bolted onto the pipe lines using flanges for 50 mm diameter and larger; for smaller than 50 mm diameter, connections shall be means of high pressure hose clips and sealed with rubber plastic.
Chilled Water Expansion Tank
The Sub-Contractor shall supply and install chilled expansion tanks of capacities as shown on the accompanying drawings. The tank and curved roof shall be constructed from not less than 3/16” thick galvanised iron sheet, treated with anti-rust paint and suitably insulated with 2 ins. of Onazote or equivalent and sheathed with 20 gauge sheet which shall be sprayed with two coats of anti-rust paint.
The tank shall be fitted with a make-up line to be connected to the domestic cold water supply main in the building. A suitable ball float valve, overflow drain, quick-fill line, water level gauge to approval and connecting line to return chilled water pipe shall be fitted to the tank.
The tank shall be supported on steelwork which shall be of welded angle iron construction or on concrete plinths.
Execution
Installation
Provide automatic air vents at high points of all piping and as required for removal of air from the system using 20mm steel pipe suitable for pressure service between the main pipe and inlet. Provide 10mm OD hard drawn to BS 2871 Table X copper tubing from vent outlet for overflow in case of defective action. Copper tubing shall run into suitable drain. When vents are located above hung ceilings, connect all vent drains to a common drain main and pipe to nearest service sink or floor drain. Provide 20mm stop valves in the inlet line for servicing of automatic air vent. Manual vents may be substituted for automatic vents, at system high points, only as directed by the Employer’s Representative.
Provide at each heat transfer element supplied with water, not less than one 15mm manual air vent.
Provide manual air vent valves in the piping connections to each chilled water coil (both supply and return where such are not automatically vented). Provide a 7.5mm vent line from each line to nearest floor drain, or as directed, to suit job conditions. At Employer’s Representative’s discretion, provide soft temper copper tube pigtail on manual vents, in lieu of 7.5mm vent line, so that vent can be discharge into a bucket.
Low point drain shall be installed at the bottom of all risers.
Pipe Thermometers
Provide thermometers in the inlet and outlet at each of the following locations:-
Chilled water cool
Pipe headers and common headers
Heat exchanger primary/secondary inlet/outlet
Pressure Gauges
Provide pressure gauges at the following locations:-
- Upstream and downstream of all coils
- Upstream and downstream of pumps
- Primary/secondary of Hex inlet/outlet
Strainer Installation
On open systems, install strainers immediately upstream of each automatic control valve with the same size as the inlet pipe indicated on the drawings, not reduced size serving the control valve.
Provide approved valve dirt blow-out extensions on each strainer. Locate each blow-out valve at hand-height.
Clean the strainers as necessary until accepted by Employer’s Representative.
Provide temporary strainer in the suction line of each pump during construction, testing and balancing. Replace with permanent strainers after acceptance by the Employer’s Representative.
Minimum strainer body at pump inlet connections shall be 80mm.
Prior to installation, disassembled strainer, coat with anti-corrosion compound and re-assemble.
Install strainers with ample space for basket removal. Provide quick opening 25mm blow-off valve with cap.