Installation and Start Up – Water Tanks
Standard commercial water storage tank installation procedures must be followed. The tank must be set and correctly connected to the system under the supervision of an experienced installer in accordance with local regulations, which usually mandate minimum clearances between equipment and in front of manways.
Tanks must be handled carefully to avoid damage, linings and insulation are especially vulnerable. Installed lifting lugs are for lifting empty tanks only.
Exposed primed surfaces should be topcoated before startup.
Supports are designed to withstand likely seismic and wind load events when attached to a suitable base such as a concrete pad on grade. The services of a Structural Engineer will be required in some cases.
Unless we were advised otherwise, tank supports are designed with an importance factor of 1, except on our stock vertical glass lined hot water tanks, when it is 1.5.
(See here for information: http://hansoncatalog.com/californiatitle24.html) Your State may have similar rules.
All controls, valves and gauges installed must be compatible with the pressure and temperature ratings of the tank as listed on the name plate.
Water leakage from the tank for any reason must be contained to prevent damage to its surroundings.
Hanson Tank accepts no responsibility for consequential damage however caused.
Failure to follow these guidelines may void your warranty.
Incorrect installation can cause rapid failure of water tanks due to electrolysis. It is vital that this risk is reduced by the use of dielectric connections and isolation of the tank supports. Installers must be aware of the correct procedures. For assistance call 1 (213) 747-7514. To be certain all dielectrics are correctly installed, check the final installation with an ohm meter. There must be no circuit between a pipe and the empty tank.
Always refer to packing slip for additional instructions.
FNPT connections have plastic plugs installed for shipment. They must be replaced with permanent fittings before the tank is filled.
The tank should be installed in such a manner, that should the tank or any connections to it leak, the resulting flow of water will not cause damage. All tanks will eventually leak.
A good policy is to monitor the condition of the inside of the tank periodically, so that any deterioration can be repaired.
Manway and Handhole Installation
Manways and handholes shipped with tanks were not used for pressure testing but are loosely installed later so they will not be lost in shipment. The gaskets may shift due to vibration in transit. Covers are in place for shipping only, and must be adjusted and tightened both before and after the tank is pressurized. The bolts are not tightened completely so that the tank can be opened and cleaned prior to service. At this time make sure that both gasket surfaces are clean as some lining residue might remain. Before the tank is brought up to pressure the bolts must be tightened sufficiently to hold the gasket in place and again afterwards as compression of the gasket by internal pressure can loosen them. If a leak occurs, try readjusting the gasket as tightening the bolts often damages the gasket. Once the bolts are fully torqued, the gasket often cannot be reused.
Replacement gaskets are available from us. When ordering, please have the tank serial or drawing number available for correct sizing.
Prices are here: http://hansoncatalog.com/tankparts.html
EPOXY LINED TANKS:
These linings are applied in multiple coats over a sandblasted surface. They contain organic solvents that although non toxic, have a distinctive odor. Our epoxy lined tanks are force cured by hot air before shipping, but it is also advisable to remove the plastic plugs and leave them open for as long as possible before start-up, so that the solvent has evaporated and any odor is gone beforehand. This is particularly important if hot water is likely to remain stagnant in the tank for long periods, especially if the use is such that any trace of taste or odor is unacceptable, in which case a different lining should be used. Once immersed, any residual solvents take much longer to disperse.
After installation, fill the system and run at operating temperature for at least one day in closed loop mode. Then drain system, open tank, and wipe clean. Pipe dope left in the tank can cause odor.
GLASS LINED TANKS:
Sacrificial anodes are supplied with all our glass lined tanks. Most tanks come with flexible anodes shipped loose in a box accompanying the tank. Some have rigid anodes which are installed here. A few tanks have both types, usually placed to protect certain areas of the vessel, for example near a heater bundle. All anodes should be checked 12 months after start up. Their original diameter is 1-5/16″. Should their diameter be reduced by 50% or more, they should be replaced. After the first check at 12 months, a schedule should be established for future checks as erosion rates vary.
We supply 25 grams of anode per square foot of tank area. Replacement anodes are available; when ordering, please have the tank serial or drawing number available for correct sizing.
Glass lined tanks must be handled with care as the lining is brittle and easily damaged.
CEMENT LINED TANKS:
Cement lined tanks must be kept closed before being installed so that the cement will remain moist and will cure without cracking. When installation of the tank is started, or if the tank is stored, add more water to the interior, so the cement will continue to remain moist. If cement lining is ever allowed get completely dry it will crack and will not protect the tank from corrosion. Please refer to the sticker near the manway.
Cement lining erodes over time, especially in tanks with high flow rates. The lining must be inspected annually and repaired as necessary while in service. If optional anodes are installed they must be inspected and maintained as for glass lined tanks. (See above). Cement lined tanks must be handled with care as the lining is brittle and easily damaged.
Foam insulation is applied at ambient temperature, nominally 70° F or more and curing continues for several more days. This is accelerated by extra heat, notably during system startup. The bond of the foam to the tank is also affected and the combination of the reactivated expansion of the foam and the weakened bond can lead to blisters forming in some cases. To avoid this, it is important to bring the tank temperature up as slowly as possible, giving pressure in the closed cell foam time to dissipate. Once fully cured, there should be no further problems. Make sure that the topcoat is good condition, it can be touched up with white roof coating if necessary.
Fiberglass insulation with metal jacket must be handled carefully, as cosmetic damage cannot be easily repaired. Its seams are silicone caulked for a weather resistant seal and they should be checked and repaired periodically in service. Aluminum jackets are anodized for corrosion resistance but can be painted if required.
Buffer tanks increase efficiency by adding extra volume of water into the system so that the boiler or chiller on/off cycles occur at the most cost effective intervals.
As in the introduction, and installed in the appropriate position in the system for maximum efficiency. Sized per industry standards. (For help in sizing, please contact the Factory).
All our bag tanks are shipped with a 12# air precharge. Before installation, check that it is within the range of 9-15 lbs at the charging valve with an accurate gauge. If it is not within this range, or any other questions come up, call factory at (213) 747 7514.
If OK, set the tank in place and connect the piping. Do not remove the top plug or loosen the nut on the cover plate as this will result in the loss of the precharge. (On top outlet tanks the plug is located on the bottom of the tank). The precharge should set at 5 lb below the minimum system pressure during installation while the system connection is open to atmosphere.
Before filling the tank, the precharge can be adjusted up to 80 psi for a 125# system. If a higher pressure unit has been supplied, the maximum allowable precharge will be indicated on the tank. Check all connections, plug and cover plate thoroughly for leakage before startup. All valves in the supply line must be fully open to purge any residual air from the piping to make sure the bladder is filled 100% with water.
These must be installed using the same procedures and safeguards as for storage tanks.
Many are lined, and if so the recommended lining inspection routine should also be implemented.
If it is the type that has an air compressor mounted on the vessel, the manufacturer’s installation and maintenance guidelines must be followed for the system to function effectively. Any maintenance or replacement parts required should be ordered direct from the compressor manufacturer.
Hydropneumatic tanks that are designed to absorb water hammer in large systems are subject to above average stresses and should be examined regularly for signs of damage by an expert while in service.
Special design and construction rules apply to tanks that will experience cyclical or repetitive loads from any cause. In these cases we must be informed the specifics in advance so that the tank can be designed and manufactured to perform as intended.
If a new tank is a replacement we do not guarantee to match prior dimensions exactly, particularly if the tank is not of our manufacture. The Code, steel availability and production methods change constantly and heat and cooling cycles during welding and some lining processes create distortion which can result in small differences from some drawing dimensions. As a result, expect to adjust existing piping accordingly.
This also applies to the tank supports, which might also change due to stricter seismic standards than before.
Even with new installations, we highly recommend that no floor bolts or studs be permanently installed before the tank is received.
Copies of the submittal specifications are available on request: Hanson A.S.M.E. Water Storage Tanks, Epoxy Lining, Glass Lining, Cement Lining, and Insulation (foam with topcoat or fiberglass with metal jacket).
Roy E. Hanson Jr. Mfg., rev Mar 2016.