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GRP Water Tank Installation Method Statement

Installation of GRP Water Tank will be carried out by specialist contractor base on the following steps and shall be done in accordance with the approved shop drawings and specification and approved material submittal ensure properly coordinated with the civil contractor for exact dimensions of the base plinth of the GRP water tank mountings and floor plan for the structural. Markings shall be done for reference.

Working inside GRP Water tank will not proceed unless all safety regulations and procedure are met for a Confined Space.


Ensure all major components of the tank are complete and available as illustrated on water tank cutout list attached in the material submittal.

Step -1: Identify all the panels using the parts list.

Step-2: The drain panel shall be fixed on the bottom of the tank base which is shown on the approved material submittal and registered manual of the manufacturer guides and layout the exact location to be confirmed prior to assembly.

Step-3: The manhole cover shall be fixed on the roof of the tank. But it can be fixed after all the side walls and base of the tank is assembled should be fixed above the inlet connection to facilitate access to the ball valve if required

Step-4: The side panels of the tank at 1.5 meter high or more are designed to receive the inlet and outlet and overflow connection flanges.

Step-5 Ensure inlet and outlet and overflow must coordinate with given elevation of the incoming piping network. The side panel at 1 meter high is not design to receive flange connection it will come up with a flat surface panel make sure having the right location.

Pre – Final Assembly of the side Panels

Step-1: Fix the patch T on the lower side of all the side panels.

Step-2: Take 2 side panels and put the sealant between them make sure that the holes of the sealant correspond to the holes of the panels between A&B panels.

Step-3: For 1.5 meters high tank, take one frame angle and fix it with the 2 side panels by using 2 bolts at each end.

Step-4: For 2 meters high tanks, take one U frame 2 meters and fix it with the 2 side panels by using 2 bolts at each end.

Step-5: Insert bolts at one side of the panels and then nuts and washers at the opposite side for every hole do not tighten hard at this time.

Step-6: Repeat the above steps 1 to 5 to fix all panel assembly which one side wall, and then stock aside.

Step-7: Repeat steps 1-5 for the other 3 side wall assembly of the tank.

Step-8 On 2 set of side panels out of the 4 sets, add corner angles. GI on each side the procedure to fix these corner angles is the same as joining two panels together. Nevertheless, there are no U frames or corner angles, and the Sealant and patches used are different.

Pre-Final Assembly of the Roof Panels

Step-1 Take 2 roof panels and put the sealant between side panels A&B

Step·2 Pierce holes through the sealant ensure equal distance between holes in the frame of the panel.

Step-3 Insert SIS bolts and washers at the opposite side for every hole. Do not tighten hard at this time. Follow manufacturers manual.

Step-4 Repeat the above steps 1-3 until one full row of roof panels is assembled and then stock aside.

Step-5 Repeat the above procedure 1-4 for all the rows of tanks roof.

Note: Do not forget to put the manhole cover instead of one of the roof panel by choosing its correct location as per manufacturer recommendation and user installation manual for GRP water Tank.

Pre-Final Assembly of bottom Panels

Step-1 Fix Patch on the corners of each bottom panel.

Step-2 Take 2 Bottom panels and put the sealant S Between them. Make sure that holes of the sealant S correspond to the holes of the panels as shown manufacturers’ installation manual.

Step-3 Insert bolts, nuts and washers at every hole. Do not tighten at this time.

Step-4 For 2 meters High tanks, use the big washers instead of small washers.

Step-5 Repeat above steps 1-3 until one full row for bottom assembly panels is ready and stock aside.

Step-6 Repeat the above steps 1-4 for all the rows of tanks bottom panels.

Step-7 Do not forget to put the drain panel instead one of the bottom panels by choosing its correct location.

Procedure for Final Assembly

Take note that after all pro-final assemblies of panels, the final assembly of the tank body should be done as follow:

The bottom of the tank, then the 2 opposite side walls which contain the corner angles, then the roof of the tank, and at the end the tank shall be closed by installing the balance 2 side walls which contain the corner angles.

Final Assembly of tho Bottom panels

Step-1 Take all bottom panel rows and put them side on the foundation in their upright position, convex side up.

Step-2 Insert continuous Sealant S between all the rows and insert bolts, nuts and washers. Mention on the pre-final assy. of bottoms (base panel)

Step-3 Tighten all bolts of the base panel (bottom panel)

Final Assembly for two of the four side walls

Step-1 Fixing of the side walls have to be done in two steps mentioned in the above sections

Step-2 Fix a side wall, stick the sealant S and insert the bolts in the bottom Panel holes where the side walls will be joined.

Stop-3 lift a side wall and put it standing near the bottom panels while inserting the bolts in its holes.

Step-4 Fix nuts and washers. Apply note on section mentioned do not tighten hard at this time.

Step-5 For 2 meters high tanks, use long nuts instead of normal nuts at the lowest hole. This will help to fix the U frame supports at later stage.

Step-6 Repeat the same procedure 1-4 for the other side wall panels on the opposite side.

Final Fixing For the Roof Panel Rows to tho Tank Body

Step-1 Stick the sealant on the side panels’ upper holes.

Step-2 Lift Roof panel Row and insert it between the two standing side walls while inserting the SIS bolts in the holes of the side and roof panels.

Step -3 Fix a Roof support plate and roof support poles as shown in the sketch here-under, and then fix SIS nuts and washers. Do not tighten hard at this time.

Stop-4 Repeat the same procedure 1-3 for the other roof panels’ rows.

Closing Thank Body: Fix the last two side walls containing the corner angles using the same procedure as mentioned above

Fixing the Accessories

Step-1 U-FRAME Supports: For 2 meters high tanks, fix the U-frame supports to the long nuts using the bolts. Refer to manufacturer registered manual.

Step-2 Fixing Flanges For Inlet and Outlet ensure using rubber capped bolts sets , type of flange and material and Rubber gasket material must be compatible to the medium element.

Step-3 Ensure that no face problem encountered during and after the connection installation for Inlet & Outlet, Overflow and Drain as per manufacturers recommendation

Step·4 Ensure Air Vents Installed at Highest Point. (Above Tank Roof)

General Requirements for GRP Water Tank Installation

Ensure Initial Hydro test must be done by site operatives and assisted by Supplier or manufacturer representative and submit report for Record that no leakage during initial testing with all parameters from Tank to Piping connection.

Clean the Water tank inside and outside remove protruding sealant patches.


Ensure all valves installed are square and plumb allowing sufficient access during operation and maintenance. Nuts, bolts and clamps are also to be checked to ensure proper tightness.

Do not connect coupling/flange until the adjacent pipe alignment and pipe supports is checked for correctness to avoid any further modification.

Make sure approved tagging/labeling is provided as per specification.

Raise request for inspection and approval of installation by consulting engineer.


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