Installation Tips for Chemical Storage Tanks: Site Preparation and Offloading

Proper site preparation and safe offloading are two of the most critical steps to ensuring a long, trouble-free life for your chemical storage tank. The following best practices are distilled from Poly Processing’s Installation, Operation, and Maintenance (IOM) Manual, and they focus specifically on preparing the tank pad and safely getting the tank from the truck to its foundation. 

Before using your chemical storage tank, we strongly recommend downloading the complete IOM manual.

1) Site Preparation: Get the Foundation Right

A great installation starts with a great tank pad. Your tank’s base directly affects long-term performance, leak prevention, and warranty coverage.

Foundation essentials

• Use a flat, level, smooth, monolithic concrete foundation or a PPC-approved support pad sized to carry the full weight of the filled tank.
• Remove ALL debris immediately before setting the tank. Sweep both the pad and tank bottom. We’ve often found debris under a tank that caused tank failure — everything from nets to bolts and even PVC piping. 
• Make the foundation at least 2 feet larger in diameter than the tank when accommodating restraint clips or ladders. Consult PPC if seismic restraints will be installed.
• Provide compliant secondary containment. Poly Processing’s SAFE-Tank system is designed for a minimum of 110% containment.

IMFO® (Integrally Molded Flanged Outlet®) Tanks 

• Elevate the tank bottom above the primary floor surface using:
  • PPC polyethylene PolyBase, polyurethane PolyBase, or
  • A monolithic concrete pad with finished edges (minimum 4 inches thick) to clear the IMFO flange. Concrete pad thicknesses will vary based on several factors.
• Notch the pad to accommodate the IMFO outlet. Align the tank’s straight wall with the foundation’s straight wall at the notch.
• Limit pad projection to a maximum of 2 inches beneath the IMFO neck to prevent stress.
• DO NOT hang valves or heavy piping from the IMFO. Independently support all piping.
• Store and move IMFO Tanks with a 4x4 block under the IMFO base so it never bears weight on the ground.

Location and access

• Place all chemical storage tanks away from heat and flame, and out of high pedestrian/equipment traffic.
• Ensure safe, easy access for future maintenance, inspection, and eventual replacement. DO NOT install the tank in an enclosed location where accessing and removing the tank will be difficult or impossible.
• Provide sufficient clearance for restraint systems, ladders, flexible connections, and venting components. See Poly Processing’s IOM Manual for more detailed information on the importance of proper flexible connections and venting.

Storage prior to install

• Tanks can sit in direct sunlight; covering with a tarp helps keep them clean.
• Keep out of forklift lanes and other impact areas to prevent gouges.
• Temporarily restrain tanks or store indoors to prevent wind movement.

2) Pre-Offloading: Receiving and Inspection

Before you move anything, inspect everything. Follow these procedures:

• Inspect the tank and all loose/boxed accessories immediately upon receipt for damage or missing components.
• Note any issues on the driver’s copy and packing slip and have the driver initial it.
• Report damage/missing items within 3 working days.
• Clearly label and securely store loose parts (gauges, flexible connections, bolts, gaskets) so they aren’t misplaced before installation or used somewhere else on the job site.

SAFETY REMINDER: Do not stand or work on the tank dome. Tank domes are not load rated and are slippery — fall risk is high.

3) Offloading: Safe, Controlled Lifts

Moving a tank is a skilled activity that requires experience and knowledge. Poly Processing strongly recommends using a licensed, experienced rigger. Keep all personnel clear of the tank, rigging, and lift equipment during offloading. If moving a used tank, it must be fully drained before lifting.

Lifting with molded-in lifting lugs (preferred)

• Consult the tank drawing for the correct number of lifting lug sets (two lugs = one set). Use all lug sets if provided.
• Position the crane boom directly over the tank’s centerline.
• Use shackles with threaded pins through each eyelet. The lug hole is 1-3/8 inch diameter and spaced 8 inches side-to-side; use pins that “fill” the hole for better control.
• Ensure each shackle and cable is rated for a minimum of 3,000 lbs.
• Slowly raise the tank to vertical, balancing weight carefully. For insulated tanks, protect the foam surface (e.g., cardboard near lug areas) so rigging doesn’t gouge insulation.
• Once upright, set the tank back on the trailer momentarily to relieve cable tension and adjust rigging to the true balance point. Then lift and move to the foundation.

Important for IMFO Tanks: Before allowing the tank to sit on any surface during offloading, place a 12-inch 4x4 block under the IMFO base to prevent damage.

Using the manway (only if lugs or straps are not available)

• PPC recommends lifting lugs or truck straps underneath the tank. If not available, use a spreader bar at least 3 inches in diameter, 42–46 inches long, and strong enough for the load.
• Follow your rigger’s engineered procedure to avoid distorting the manway opening.

Using forklifts (often for positioning and uprighting)

• Use smooth, burr-free, extended tines for larger tanks.
• Tie the tank to the mast to prevent rolling/sliding.
• Insert tines from the long side (from dome or floor) to find a balance point. Move slowly and be ready to adjust.
• Set the tank on a flat, open area. Arrange 3–4 pieces of 4x4 blocking around the outside radius to elevate the tank for fork access.
• Position a second forklift opposite the first as a safety to prevent tipping as the tank is stood upright. Protect the tank by wrapping fork tips (e.g., cardboard sleeves).
• Straddle the tank radius with forks, raise to upright, then slide forks under the bottom, lift just enough to clear blocks, and transport slowly to the foundation.

SAFE-Surge lid handling (if applicable):

• SAFE-Surge emergency vent lids are heavy (about 22 lbs) and awkward—use lift equipment or scaffolding with hoisting.
• Do not use a ladder to install the SAFE-Surge lid.
• Ensure the center cap can move freely to relieve pressure.

4) Setting the Tank on the Pad

• Conduct a final check of the pad: flat, level, smooth, and clean—no trapped debris.
• Align the IMFO neck with the foundation notch; confirm pad projection under the IMFO neck is 2 inches or less.
• Verify there is no load on the IMFO nozzle and no heavy piping or valves hanging from it.
• For installations requiring restraint systems, place clips with at least 1-inch clearance between the tank and clip back to allow for some tank expansion.
• After placement, proceed with piping using flexible connections on all fittings located on the lower one-third of the sidewall for tanks larger than 600 gallons. Support all piping independently of the tank.

5) Quick Checklists

Site preparation checklist

• Monolithic, flat, level, smooth concrete pad; swept clean before set
• Foundation sized for tank weight and at least +2 ft diameter for restraints/ladders (if applicable)
• Notch and 4-inch minimum pad thickness for IMFO clearance; correct wall alignment and ≤2-inch projection
• Secondary containment sized per code (SAFE-Tank provides ≥110%)
• Clear, safe access for install, inspection, maintenance, and eventual replacement
• Temporary restraint from wind while staged

Offloading checklist

• All personnel clear; spotters assigned; exclusion zone set
• Licensed rigger engaged; lift plan reviewed
• Use all lifting lug sets; rated shackles/cables (≥3,000 lbs each)
• Second forklift present if uprighting by forklift; fork tips protected
• IMFO protected by 4x4 block whenever tank is set down before final placement
• No standing/working on tank dome

After placement (pre-commissioning)

• Flexible connections installed on lower sidewall fittings; piping independently supported
• Fittings torqued to factory values and techniques
• Venting sized and unobstructed for atmospheric tanks
• 24-hour hydro test completed before introducing chemical
• Appropriate chemical warning labels applied

Common Mistakes to Avoid

• Debris trapped between tank and pad causing point loads and wall stress
• No notch or misalignment at the IMFO outlet; more than 2-inch pad projection under IMFO neck
• Hanging valves or heavy pipe off the IMFO flange
• Skipping flexible connections on lower sidewall fittings
• Using expansion joints designed for steel systems instead of low-spring-rate joints suited for plastic tanks
• Standing or working on the tank dome
• Offloading without proper rigging or a second forklift when uprighting

Successful Installation Means a Long Tank Life

By following these site preparation and offloading practices from Poly Processing’s IOM manual, you’ll minimize installation risks, protect your warranty, and set your tank up for many years of safe, reliable service. If your application includes seismic restraints, elevated temperatures, specialty fittings, or if you have any questions, consult Poly Processing for project-specific instructions before installation. 

Download the Poly Processing IOM Manual