Double Wall Logo

Double Wall Tank Sumps

PCI’s Double Wall fiberglass tank sumps come in a variety of sizes so they can be used with a variety of monitoring and testing options to satisfy local regulations.

Interstitial Monitoring
PCI’s double wall tank sumps allow for periodic or continuous interstitial monitoring to detect liquid. Continuous monitoring eliminates the need for integrity tests.

Compatible Testing
Our double wall tank sumps are compatible with the following testing methods:
• Dry Interstitial
• Vacuum Monitored
• Fluid Filled

VPH Compliant

Shipped Under Vacuum
Before shipping, Double wall tank sumps are pre-tested and shipped under vacuum with the vacuum gauge installed for verification of sealed interstitial space.

UL Listed 2447

  • Double Wall Octagon Tank Sump

Standard Features

TwistLok Access Cover Logo
Twist-Lok Lid

Twist-Lok Access Cover

PCI’s tank sumps come standard with the latest generation of our innovative ‘Twist-Lok’ Access Cover. Constructed from injection molded fiberglass, Twist-Lok lids provide a watertight seal with a quick and easy 12º  turn.

Duo Molded Technology

Duo-Molded Technology

Our fiberglass sumps utilizes Duo-Molded Technology. Using premium raw materials with a high glass content, we create two layers of fiberglass, offering superior strength and fuel resistance.


Our signature ‘Brite-White’ interior reflects light for better visibility and makes identifying leak points easier.

100% Fiberglass

100% high-quality, non-corrosive fiberglass provides long-term reliable containment from fuel exposure without voiding warranty, warping, cracking or becoming brittle.

Epoxy Bonding EP2A

Permanent Bond

We’ve engineered our products to be the most efficient to install without losing any of the water-tight quality. Our two-piece tank and transition sumps are permanently bonded in the field with a single EP2A epoxy pour.

Optional Features

Inspection Port

Inspection Port

Optional 4″ inspection port is available for all Twist-Lok lids. This allows for quick and easy inspection without removing entire cover. Part Number IP4000-1

PCM Double Wall Octagon Tank Sumps Dimensions

Part No. Collar Diameter Base Height (A) Adjustable Height(B) Overall Height (C)
PCMDW4250 42″ 21″ 0″ – 18″ 32″ – 50″
PCMDW4850 48″ 18″ 0″ – 21″ 29″ – 50″
Options (Example: PCMDW4850-3C9)
-3C9 Collar Mount, (x2) E148CM Epoxy Kit** & (x2) GK-42 Fiberglass Kits

Optimum lid height is 4″ below manhole cover

Double Wall Octagon Tank Sump Dimensions

TSM Double Wall Tank Sumps Dimensions

Part No. Width Base Height (A) Adjustable Height(B) Overall Height (C)


4″ – 18″ 32″ – 46″ 48″


30″ 4″ – 18″ 44″ – 58″ 48″


30″ 4″ – 18″

44” – 58”




4” – 18”

44” – 70”




4” – 18”

38” – 52”




4” – 18”

44” – 64”




4” – 18”

44” – 64”




4” – 30”

44” – 76”

Options (Example: TSMDW606048D-3C9)
-3C9 Collar Mount, (x2) E148CM Epoxy Kit & (x2) GK-42 Fiberglass Kits

Optimum lid height is 4″ below manhole cover

Double Wall Tank Sump Dimensions

Additional Accessories (Ordered Separately)

Part No. Description
EQP-DW-VAC Vacuum Kit (Required for all Double Wall Sumps)
EQP-IF-5GAL Interstitial Fluid, 5 Gallons (Required for Double Wall Sumps with Fluid Filled Interstice)
EQP-IF-ADP-PC Interstitial Fluid Adapter Kit (Required for Double Wall Tank & Below Grade Transition Sumps)
Varies Double Wall Tank Collars



UL® Listed 2447

California Code of Regulation Title 23, Division 3, Chapter 16, Section 2631 (AB 2481/ California VPH)

State of Floria Department of Environmental Protection Approved / Registered Storage Tank System: EQ-203