CASE STUDY

36-in. Wastewater Process Piping External Rehabilitation

A fully structural carbon FRP system from QuakeWrap®, rated for 65 psi operating pressure and applied to the outside of a steel process pipe for Cobb County Water System, Georgia.

PRODUCT: WET LAYUP CFRP
APPLICATION: PIPE REPAIR
INDUSTRY: WATER & WASTEWATER

GET A PIPE REPAIR CONSULTATION ALL PROJECTS

Cobb County 36-in. steel process pipe loop after the carbon FRP wrap and gray UV-resistant top coat

65 psi operating pressure the FRP system was designed for

pipe diameter: 36 in.
retrofitted: 54 ft
operating pressure: 65 psi
expected service life: 50+ yrs

Project Details

OWNER: Cobb County Water System
LOCATION: Cobb County, Georgia
STRUCTURE: 36-in. steel process pipe, 54 ft
DESIGN PRESSURE: 65 psi operating
QUAKEWRAP® SYSTEM: Carbon + glass FRP, external wet layup (QW U27C, QW B2610G)
FRP SYSTEM AND MATERIALS: QuakeWrap, Inc.
FRP INSTALLER: FRP Construction

01 · THE CHALLENGE

Strengthen a Pressurized Steel Pipe From the Outside

Cobb County Water System needed to retrofit 54 ft of 36-in. diameter steel process piping at its water treatment plant.

The retrofit had to withstand an operating pressure of 65 psi.

02 · THE SOLUTION

A Fully Structural Carbon FRP System

A design-build team was selected. QuakeWrap® provided the FRP system and materials, and FRP Construction installed it using the external wet layup method.

The pipe surface was prepared by abrasive wire wheeling, then blown and wiped clean. A dual-layer glass fabric laminate went on first to make the system impermeable, form a dielectric barrier between the steel and the carbon, and add strength in the hoop and longitudinal directions. Carbon FRP layers then carry the 65 psi pressure.

UV top coat20 mil
Epoxy top coat40 mil
Carbon FRP (QW U27C)2 layers
Glass FRP (QW B2610G)Dielectric barrier
Epoxy tack coatHigh-adhesion bond
36-in. steel pipeHost

Eight photos of the Cobb County 36-in. pipe as carbon FRP layers go on, then the finished gray top coat

03 · THE RESULT

Built for More Than 50 Years of Service

FRP Construction completed the installation successfully. The expected service life of the FRP system is more than 50 years, with the UV-resistant top coat possibly replenished after an extended time in service.

pipe diameter: 36 in.
retrofitted: 54 ft
design pressure: 65 psi
expected service life: 50+ yrs