Concrete Tank – Installation Guidelines

BACKGROUND
Proper installation of each tank is absolutely critical for it to function properly and remain watertight. Many of the problems experienced with tank operation, or of tanks leaking (either water flow into or out of the tank), or of premature system failure can be attributed to incorrect procedures during installation. Improper installation practices can seriously damage the tank or other system components, can reduce the capacity or efficiency of the tank, and can even cause serious personal injury.
This INSTALLATION GUIDELINE is offered to assist the installer with advance planning, proper site preparation, safe handling and sound installation procedures. It should also prove helpful to designers, inspectors, and homeowners. It is one of the essentials for long-lived systems.

SITE CONDITIONS
PLAN YOUR PROJECT…. You will need to know the measurement from the underside of the tank to the bottom of the tank’s inlet opening in order to prepare the sub-bed elevation to allow the tank to properly receive the sewer pipe coming from the building. Review the manufacturer’s most current literature and drawings, or call them for these critical dimensions.
Keep in mind that the site where the tank is to go must be accessible by large and heavily loaded trucks (sometimes up to 50,000 pounds). This site must allow for reasonable access under the trucks own power (not be towed or pushed); it must be clear of trees and branches, overhead wires, underground utilities or other structures that could be damaged by or interfere with the delivery and off loading of the septic tank. Typically, the delivery truck must be able to safely get to within three feet of the excavation and be on stable and level ground in order to unload and set the tank.
The purchaser is responsible for any damage to the site, the delivery truck or the tank once the truck leaves the pubic thoroughfare and enters the work site. Therefore, adequate access for delivery equipment to get to the excavation and unload the tank is important.
Standard concrete septic tanks are not designed to be installed under traffic loads or to carry unusual heavy construction or maintenance equipment. (Tanks designed for traffic loadings or special situations are available by specific request.)

EXCAVATION
For the safety of your backhoe operator, and the public good, all buried utilities should be identified and located before you dig. Here is a recommended procedure:

Call before you dig to arrange for Manitoba Hydro to check and mark your property for electrical and/or natural gas lines. The service is free to locate Manitoba Hydro-owned underground facilities.

Call 1-888-MBHYDRO (1-888-624-9376). https://www.hydro.mb.ca/contact.shtml

Remember to also call any other utility or service companies which may be providing service to that location.

Please note that you must CALL. We cannot accept email requests for appointments.

From April 1 to October 31, please call at least one week ahead to book an appointment. From November 1 to March 31, we require at least two business days notice.

One call can prevent service outages, equipment damage, costly repairs, environmental pollution, personal injury, and even death.

Be prepared to provide them with the project address, how to reach you, and anything else necessary or unique about the location.

They will either send someone to mark their underground lines, or advise that their underground services are unaffected by your proposed excavation.
Do not begin digging until you have been contacted by each utility or service. Lay out your hole a minimum of 10 inches and no more then 20 inches larger than the tank, to allow space to properly compact the fill material. For worker safety, it is recommended that no worker should be in the excavation until the tank has been set.
Proper bedding is important to ensure a long service life of an onsite septic system, and to allow the tank to be set level. A sand or pea gravel layer, a minimum of 5 inches thick, overlying a firm and uniform base is recommended. Correct compaction of the underlying soil and sand/gravel bed is critical to insure the tank is set level and stays that way.
Tanks must not bear on large stones, boulders, or rock edges.

TANK PLACEMENT
First, inspect the delivered tank while it is on the truck; check for any defects or shipping damage, and note that it is the tank ordered. If there are any discrepancies, point them out to the driver, and clearly note them on both the driver’s bill of lading and your delivery documents.
Prior to placement, the tank’s orientation should be confirmed (inlet openings should face the residence). After placement, check that the tank is level, and that the inlet elevation will closely match the bottom of the pipe coming from the house at the point where it will enter the tank. Be sure that the pitch of the sewer pipe from the house to the tank meets the local Code requirements.
Setting of the tank should be done by the tank manufacturer’s truck driver. This will insure that it is handled properly, with appropriate special equipment, as may be needed.

TANK LOADING & UNLOADING
-­ Operator is to inspect the, crane, wire rope, chain hooks, lift bar and straps for any damage or excessive ware before loading or unloading any tank.
-­ The operator (Concrete Brothers Ltd. trained employee) is the only person permitted to operate the delivery truck or it’s crane.
-­ The operator is to ensure that no one is standing directly behind the tank or in an area they deem unsafe when being loaded or unloaded.
-­ No person(s) shall aid in guiding the tank until it is clear of the deck and they have been given the “Okay” from the operator to do so. When assisting in guiding the tank the operator will provide an aid and no person(s) shall be closer than 1m from the edge of the excavation.
-­ When the tank is being lower into place it is only to be guided from the side that is visible to the operator. Once the tank is within 6” of resting on the bottom of the excavation, the operator will allow a person(s) to guide the tank from the front to line up the plumbing.
-­ All spectators MUST be a minimum of 10m from the delivery truck while installing the tank.

JOINT SEALS
Use only high quality seals for all joints. Mating surfaces must be clean; at a minimum, sweep off any debris before placing the sealant. Recheck tank for joint alignment and grade before backfilling.
With time, pipes may settle, and this changed angle of pipe entry/exit will begin to leak unless it is fitted with a flexible joint connector.

BACKFILLING
Care should be taken when backfilling, to prevent damage or misalignment to the entry and exit piping, the tank and fittings, or any joints. Backfill should be placed in uniform, mechanically compacted layers less than 24 inches thick. Do not backfill and compact one or two sides before backfilling the other sides. Excavated material may be reused for this purpose, but may not contain any large stones.
Concrete tank walls are significantly heavier than fiberglass or high-density polyethylene tanks, and are least likely to float in a flooded excavation. However, even empty concrete tanks will float if the water level rises high enough. Therefore, to prevent this from happening after the tank is set, keep water pumped out of the excavation until backfilling is completed, or fill the tank with water, or place soil on top of the tank.