Installation, Insulation & Testing Of Condensate Drain Pipes
This method statement describes how to install all condensate UPVC pipes for fan coil drains and galvanized pipework for AHU drains on-site. It also covers insulating the galvanized steel and UPVC pipes and providing supports, anchor points, and expansion for the condensate drainage system.
Table of Contents
This method statement outlines the procedure that will be followed to guarantee that the condensate drain pipework system, which includes all pipes, tubes, fittings, expansion and contraction devices, hangers, anchors, supports, and all other accessories and components, will be installed as an integrated piping system. Additionally, it is important to ensure that the installation, final connections, and workmanship adhere to the contract’s terms and the project’s specifications.
All vertical and high-level pipework must be solvent-welded UPVC pipe. Before erection and before being covered up, pipes will be completely cleaned and free of burrs, rust, scale, and other flaws. Materials that the client must submit and review.
Responsibilities
The site engineer, supervisor, and QA/QC shall be responsible for implementing this method statement during site construction.
Pre-Requirements Before Installation
All materials and documentation are relevant to condensate drain piping works will be checked by the site engineer/supervisor before the commencement of work, ensuring that these are of the correct type as per approved submittals and approved by the client.
Prior to the commencement of any construction activity, areas, and access will be inspected to confirm that they are in a suitable condition for pipe installation works to commence.
Before the commencement of any construction activity, pre-inspections will be carried out on all materials prior to them leaving the storage area.
Method of Installation – Galvanized Steel Pipe
The supervisor will instruct tradesmen regarding the execution of the works and will distribute all necessary approved construction drawings of the latest revision. The supervisor will also check that tools, equipment, and all materials available comply with the contract requirements.
Ensure approved sleeves have been installed at the required locations and are of the same material as the service passing through them (these sleeves will be installed as the civil structure progresses).
By means of string and chalk lines, the actual pipe layout will be identified to allow pipe supports and anchors to be installed.
Condensate drain pipework will slope towards the drain discharge point. When using a spirit level, a bubble turn shall be adequate to identify the correct slope.
At discharge points either directly above the funnel drain on the grey water system or sump pit, the condensate discharge shall be visible, i.e. drain line and the funnel will not be directly connected.
All tees will be the same size as the pipes connected to them; bushed outlets shall only be used if the required outlet size is not of standard manufacture.
Reductions will be made by means of straight-through reducing sockets. Reductions on bends by bushes will not be used.
Eccentric reducing sockets with the flat side at the top shall be used to avoid air entrapment in the system and facilitate the slope to drain off the pipework.
Supervisor to ensure that where pipes cross construction, expansion joints ‘bellows’ type expansion joints are installed in the system, as detailed on the construction drawings and in accordance with technical submission reviewed by the client.
All pipework systems shall be provided with adequate removable sections to assist with cleaning and for ease of maintenance operations.
Supports will be arranged as near as possible to pipe joints in case of a change in direction. Additional supports will be added within 300mm of any branch lines.
GI Pipes Jointing Method
Screwed pipework and joints up to and including 50mm mild steel pipe.
The use of an appropriate threading machine will thread pipe ends.
The machine dies head will be suitable for cutting tapered type threads.
Threads will be cut to the correct thread length.
After the suitable thread has been cut, burrs, surplus oil, and swarf will be removed before the selected fitting is screwed in place.
Threads shall be applied with thread joint compound of the approved type.
By means of an appropriate pipe wrench, the selected fitting will be screwed onto the pipe thread to the correct tightness required without causing any damage to the pipe/fitting.
When pipe and fitting are fully tightened, clean of any excess jointing compound, and paint exposed threads with approved cold galvanizing compound.
Method of Installation for UPVC Pipework
Vertical pipework will be supported at the base or as the approved construction drawing indicates.
Condensate drain pipework will be installed so as to allow sufficient space for expansion or contraction and thermal insulation.
Pipework will generally run parallel to the alignment of the adjacent building services and as close to the construction as possible, sloping towards the drain point.
Pipework installed at a high level over passages shall have a clear headroom of 2 meters from the finished floor for the plant operator.
Pipework connections to equipment will be via three piece union and a sealed trap. The configuration will be sized to maintain a seal under full operating load, dirty filter, and wet coil conditions of the AHU and Fan Coil Units.
According to the next table, installations shall comply with General & Particular Contract Specifications.
Pipe Jointing Method for UPVC Pipes
Pipe solvent – welding for piping up to 80mm. Cutting will be done in a neat workman-like manner without damaging the pipe, and all ends will be chamfered and deburred.
Using the correct cleaning solution (in accordance with the manufacturer’s recommendations and instructions), the pipe end and fitting will be thoroughly cleaned and decreased.
The pipe end and fitting will be jointed without solvent, marked for alignment, and depth socket.
Remove the pipe from the fitting, apply solvent cement, and rejoin the pipe and fitting, ensuring alignment and depth marks correspond.
When carrying out this procedure, ensure adequate ventilation and suitable fire fighting equipment are available. i.e. blanket and or extinguisher for extinguishing the fires.
Air Testing of Condensate Drainage Piping
Fully charge water seals of all condensate traps.
Insert test plugs in all open ends of pipework.
Test with air using a hand pump with a rubber hose connected to one test plug via a female-to-nipple adapter.
Connect the rubber hose as item 9.3 and a manometer until a test pressure of 38mm water gauge is reached from another test plug on the system to be tested.
This pressure will be maintained for 1 hour.
Water Testing Condensate Drainage Piping
Insert test plugs in all open ends of pipework.
Fill the pipe with water up to the flood point of the highest connection.
The static head will not exceed 1200mm at the high point of the test and be maximum of 2400mm at the low point.
Maintain this pressure for 1 hour or as per specification requirements.