5. PRE-INSTALLATION NOTES

5.1 TANK OPERATING CRITERIA

5.1.1 TEMPERATURE - All standard TWIN TANKS tanks are designed for a maximum continuous service temperature of 100° F. Service temperatures greater than 100° F reduce the strength of the tank. Applications with temperatures greater than 100° F require greater wall thickness to accommodate this reduction in strength. Please consult factory for applications with service temperatures greater than 100° F.

5.1.2 PRESSURE - All standard TWIN TANKS tanks are designed for use at atmospheric pressure. Pressure or vacuum situations can cause excessive deformation or damage to the tanks and void warranty. Please consult factory for applications which may develop pressure or vacuum situations.

5.1.3 CHEMICAL COMPATIBILITY - Suitability of the tank assembly (tank, fittings, gaskets, etc.) for storing a particular chemical must be confirmed by chemical data (this should have been done by the tank distributor or the end user prior to placing the tank order). However, changes to the tank (i.e. tank accessories, or the service of the tank) can occur. Please consult the factory with any questions.

5.1.4 LOCATION REQUIREMENTS - There may be location requirements which should be considered prior to placing the tank into service. Some items to consider are: secondary containment; locating the tank in a flood plain; locating the tank so it is easy to install and access for service; locating a tank in an area where seismic or wind forces may be experienced; and heat from surrounding equipment. It is the responsibility of the end user to ensure that all location requirements have been taken into consideration. Check for all federal, state, and local regulations that may apply to the tank installation. A thorough evaluation of the proposed tank location prior to tank installation is recommended.

5.1.5 TANK ENTRY PRECAUTIONS - If entry into the tank is necessary, be sure to take all necessary precautions and follow all applicable regulations. Entry into a tank should be considered a “CONFINED SPACE ENTRY” with appropriate OSHA safety precautions required. There are many safety practices which should be considered depending on the specific conditions at the site. Please follow all local, state, and Federal rules and regulations.

5.2 FOUNDATIONS AND SUPPORTS

5.2.1 Vertical flat bottom tanks should be positioned on a concrete pad providing adequate support and a method to attach a tank restraint system (see Section 8 for restraint system pad placement criteria). The pad should be clean, smooth, and level so it fully supports the entire tank bottom with no deflection. The construction site engineer must design an appropriate concrete pad based on the specific application. A sand mound support can be placed under the tank bottom to promote tank drainage and extend tank life in certain applications. This is recommended for all tanks 10,000 gallons and larger. The sand should be a construction grade utility sand or finer. The tank and pad placement must be done to prevent any erosion of the sand from under the tank. Please refer to Figure 5.1. The sand mound must be very uniform without lumps or foreign objects. Per the chart in Figure 5.1, draw a circle on the tank pad and rake the sand uniformly with zero elevation at the circle perimeter and an elevation in the center per the chart in Figure 5.1. The chart recommendations are nominal dimensions. The best support is a sand mound that follows the normally convex shape of the tank bottom. If the tank bottom is not as convex as the dimensions shown for the sand mound in Figure 5.1, then follow the tank bottom. Adjust the sand mound shape/size so the tank has minimal contact with the sand when properly centered on the mound.

5.2.2 Vertical flat bottom tanks with SUMO fittings may require a notch in the concrete support pad just in front of the SUMO fitting for piping and piping accessories. The SUMO fitting has a ±5° tolerance for fitting projection off horizontal. Since the SUMO fitting comes out from the tank very near ground level, concrete support pads which project past the SUMO fitting may interfere with the SUMO and/or its piping accessories. TWIN TANKS recommends that the support pad be notched to provide adequate clearance for piping and tank expansion/contraction movement. Please refer to Figure 5.2.

5.2.3 Cone bottom or horizontal tanks require specifically designed support structures. Inadequate or improperly designed support structures may cause premature tank failure. Therefore, any support structure that is not of TWIN TANKS manufacture must be approved by TWIN TANKS in writing or ALL WARRANTIES WILL BE VOIDED.

Figure 5.1

Figure 5.2

5.3 TANK FITTINGS AND CONNECTIONS

5.3.1 Most tank fittings are typically left installed in the tank. Some fittings are not installed due to damage potential or customer request. Customer job site fitting installation insures proper gasket compression and minimizes fitting damage potential. Some distributors sell or install their own tank fittings or accessories. These fittings or accessories are not warranted by TWIN TANKS.

5.3.2 All tank connections must have adequate provisions for tank expansion/contraction due to temperature and load changes. See Figure 5.3. These provisions should allow 4% dimensional movement. Rigid piping must not be directly connected to tank outlets. TWIN TANKS strongly recommends using expansion joints or other provisions for all tank connections. Please see the hose connection example in Figure 5.4. TWIN TANKS has developed the Flexmaster expansion joint for 2" and 3" bolted tank connections. Please see section 7.11 for more details. The use of rigid piping or the failure to provide for the expansion of the tank will void all warranties.

Figure 5.3

Figure 5.4

5.3.3 FITTING INSTALLATION GENERAL GUIDELINES - If fittings are to be customer drilled and installed, there are some general installation guidelines which may be helpful.

5.3.3.1 LOCATION - It is very important that fitting location be carefully considered prior to cutting any holes. TWIN TANKS recommends (fitting size dependent) a 6" minimum centerline height for fittings on tanks less than 3000 gallons with the fitting gasket at least 1-1/2" above or below the end of any tank knuckle radius. TWIN TANKS recommends (fitting size dependent) a 9" minimum centerline height for fittings on tanks 3000 gallons or larger with the fitting gasket at least 3" above or below the end of any tank knuckle radius. TWIN TANKS recommends locating all fittings so gasket seal areas do not go through any tank flange lines or any molded-in tank feature (i.e. gallonage markers, logos, ribs, edges of tank flats, etc.). TWIN TANKS does not recommend field cutting and installation of fittings on insulated tanks. Fittings must be located to avoid interference with tie-down devices and to allow for tightening of fittings nut(s). Mark all of the proposed fitting locations with a marker. Re-inspect all of the locations prior to cutting any holes.

5.3.3.2 TOOLS - It is very important to obtain the correct tools before attempting to install any tank fitting. Tools you will need for installing tank fittings properly include:

• Marker for laying out holes
• Tape measure, straight edge, plum-bob (to align fittings meant to be aligned), etc.
• 1/2" drill motor
• Hole saw sized to the O.D. of the fitting body if bulkhead style (see section 6.1, and 6.2).
• Hole saw sized to the I.D. of the fitting flange hole or the same size as the fitting's size if flange style (see section 6.3, and 6.5).
• Drills for any bolt holes (size +1/16" larger than the size of the bolts)
• Deburring tool (a drum sander and 150 - 220 grit sandpaper may also be used)
• Wrenches (adjustable, sockets, strap wrench, etc.)

5.3.3.3 PROCEDURE

1. Disassemble the fitting and use it as a final location check as noted in 5.3.3.1.
2. With the center hole marked, cut the tank hole using the correct size hole saw (see 5.3.3.2).
3. If the fitting is a flange style (see section 6.3 and 6.5) then mark one of the bolt holes using the outer flange. The bolt holes should be oriented so the bolt holes straddle the principal centerline of the tank. With the hole correctly located and marked, drill the bolt hole.
4. Temporarily install one bolt and position the flange over the main fitting hole.
5. Mark the bolt hole opposite the bolt hole already drilled and drill that bolt hole.
6. Temporarily install another bolt and drill the remaining bolt holes using the flange as a guide.
7. With all of the fitting's holes drilled, gently deburr the hole(s) with the deburring tool. Do not put any nicks or scratches into the tank. Sand any nicks or scratches out with sandpaper greater than 120 grit.
8. Clean away any debris from the sealing surface of the tank.
9. For tanks greater than 1/2" thick, measure the tank wall thickness. If the wall thickness is not consistent within ± 1/32" around all of the fitting hole(s), some sanding on the inside of the tank wall will be necessary. This must be done carefully and as little as necessary. The purpose of the sanding is to make the wall thickness even, not to create a flat on the tank wall. The final finish sanding should be done with greater than 120 grit sand paper (preferably 220 grit).
10. With all of the fitting's hole(s) prepared, install the fitting using the instructions from the appropriate section (6.1, 6.2, 6.3, or 6.5). The inside tank wall surface must be clean and smooth at time of fitting installation.

5.4 TESTING AND FINAL INSPECTION

5.4.1 After all fittings are installed and all connections to the tank have been made, fill the tank with water and hold for at least 5 hours to identify any leaks. A record of the water pre-test must be submitted to TWIN TANKS to validate the tank warranty.

5.5 ACCESSORY PARTS

5.5.1 Various parts must be packaged separately to prevent damage during transportation. These parts are usually bagged or boxed to prevent loss or damage. Some parts may be shipped inside of the tank.