How to install tanks

Saudi Polycon underground tanks

1. Excavation

• Select a site with good sub-soil drainage.
• Excavate to a depth that gives at least 15 cm of cover over the top of the tank. This avoids over-expansion of the tank and possible leakage.
• Allow 45 to 60 cm on all sides of the tank. Failing to do so could cause the tank to collapse.
• Bed the tank on a smooth concrete floor, and level it before installation.

2. Backfilling

• Backfill in 30 cm layers and compact each layer, always compacting the ends first.
• The maximum backfill over the top of the tank is 15 cm.
• Cover the backfill with a 15 to 20 cm concrete slab, so that no external load rests on the top of the tank.

Caution: fill the tank with water as you backfill, keeping the water level even with the backfill as you go, to prevent the tank collapsing.

3. Backfill materials

• The preferred material for backfill around and over the tank is a sand and gravel mixture, and the tank must be filled with water while backfilling.
• All fill must be free of wood, masonry debris, silt and clay.

Cautions

• Do not install a tank in water-saturated clay or where the water table is high: the tank may collapse and its contents escape.
• Tanks are not fire resistant. Do not store or install a tank near an open flame, or expose it to heat above 75 °C.
• Do not install a tank under the path of vehicles or heavy equipment.
• If the tank is pumped out for normal maintenance, refill it immediately.
• Tanks left empty underground may collapse: do not let the water fall below 25% of the tank's capacity.
• Protect the tank from sharp objects that could puncture it and cause a leak.

Underground fiberglass tanks

1. Excavation

• Select a site with good sub-soil drainage.
• Excavate to a depth that gives at least 20 cm of cover over the top of the tank, to avoid damaging it.
• Allow 45 to 60 cm on all sides of the tank. Failing to do so could cause the tank to collapse.
• Lay at least 15 cm of selected bedding material over the concrete bed, and place the tank level.

2. Backfilling

• Sand bags may be placed along the bottom of the tank to stop it rolling or moving.
• Backfill carefully in 15 cm layers so that no voids are left under the tank, compacting each layer if necessary.
• The maximum backfill over the top of the tank is 20 cm.
• Cover the backfill with a 15 to 20 cm concrete slab, so that no external load rests on the top of the tank.

3. Backfill materials

• The preferred material for backfill around and over the tank is a sand and gravel mixture.
• All fill must be free of wood, masonry debris, silt and clay.

Cautions

• Do not install a tank in water-saturated clay or where the water table is high: the tank may collapse and its contents escape.
• Tanks are not fire resistant. Do not store or install a tank near an open flame, or expose it to heat above 75 °C.
• Do not install a tank under the path of vehicles or heavy equipment.
• If the tank is pumped out for normal maintenance, refill it immediately.
• A tank left empty underground for too long may collapse: do not let the water fall below 25% of its capacity.
• Protect the tank from sharp objects that could puncture it and cause a leak.