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Home / Fire Suppression System / Method Statement for Horizontal Four Flange Bladders Installation in Tank

Method Statement for Horizontal Four Flange Bladders Installation in Tank


Visually inspect bladder for correct size and obvious defects such as perforations before starting.

Lay bladder on a dry, clean surface such as a cleanly swept floor, tarp, etc. Smooth out all wrinkles and folds. Roll up the small flange necks at top and bottom of bladder, the use duct tape to tape securely so that they will easily fit through top and bottom flanges of tank. Roll up and tape the large flange necks so that that they will fit through end flanges easily.

Examine the inside of the tank shell to be sure there are no sharp objects inside the tank. Use a vacuum cleaner to thoroughly clean the inside of the tank shell. Check the interior vent hose (Green hose inside shell) is attached to both the top and bottom vent/drain screens. Utilizing three (3) lengths of rope, tie one length to one large flange neck and two other lengths to the small flange necks on the bladder. Ropes should be should be a few feet longer than total length of tank.

Folding Procedure

Fold the bladder along the long axis enough times to allow it to fit through the end flanges. Fold in a manner to allow the top and bottom flange necks to be easily accessible. Do not twist or roll bladder. Tape the folded bladder every 2 feet down the length of the bladder to hold the folds in place. Fish the rope from one of the small bladder flanges through an end flange and then through to the top flange on the tank. Fish another rope from the other small bladder flange through the end flange to the bottom flange on the tank. Fish the remaining rope from the end flange on the bladder through one tank end flange through to the opposite tank end flange.

(NOTE: All ropes must be on the same side of the interior vent hose.)horizontal-bladder-tank-installation Method Statement

Insert the bladder into the tank by pushing it through the tank end flange. Do not pull the bladder into the tank with the ropes. Have someone gently pull on the ropes as the bladder is being pushed through the tank flange to take up the slack. Do not twist the bladder while installing. To aid insertion, grease may be applied to the flange openings on the tank.

Be sure to undo each taped area just before it goes into the bladder tank. Do not remove tape from the flanges. Except for the tape on the flange areas, the tape should be removed before the bladder is pushed into the tank. Once the bladder is completely within the tank, pull the top and bottom bladder flanges out through the top and bottom openings of the bladder tank. Take the tape off the top and bottom bladder flange necks and remove the ropes.

Put steel flanges in place on top and bottom tank flanges to hold bladder in place if necessary. Only two bolts are needed per flange at this time. Make sure bladder and bladder flanges are not twisted. Remove tape from end flanges and smooth the inside so it conforms to the inside surface on the end flanges.

Connect a vacuum cleaner to the tank shell vent valve on top of tank (Do not connect to bladder vent valve on top flange). Close shell drain valve, open bladder vent valve, turn on vacuum cleaner and allow vacuum to inflate the bladder inside the tank. The bladder to be pulled against tank shell by the induced vacuum. The vacuum cleaner will change pitch when the bladder is fully inflated inside the tank shell. Turn the vacuum cleaner off, and shut the shell vent valve. When the bladder is installed properly, you should be able to look through the tank with no obstructions. Install the center tube assembly. Make sure any rough or sharp edges on center tube are eliminated. Install all flanges and tighten all flange bolts. Use a sharp bladed knife to cut out material covering flange bolt holes.

Important Notes:

  • Do not twist bladder while installing. This can complicate the installation process.
  • Do not step on, jab or poke the bladder. It can be damaged or punctured.
  • Be careful with sharp objects such as knives when cutting tape around the bladder.