Manhole specification
(A) Scope
The manhole liner shall be a FIBERGLASS REINFORCED PLASTIC (F.R.P.) LINER SYSTEM, which is resistant to the chemical environment normally found in wastewater transmission systems. The F.R.P. Liner shall be a non-load bearing component integrally cast and adequately anchored inside new precast concrete manhole sections during concrete casting process at the concrete precaster's manufacturing facility.
(1) The prefabricated F.R.P. liner shall be a one piece construction of unlayered, homogenous composite with minimum thickness shall be .12" - .20" (3 mm- 5 mm) and shall be in lengths and nominal inside diameters corresponding to the precast concrete manhole section
(2) The prefabricated F.R.P. manhole base liner shall include full flow channels with side walls to the crown of the pipe; inner surface of the bench to have an anti-skid pattern; watertight gasketed pipe bell connections or F.R.P. / PVC boot hole sleeves to suit specific pipe types, grade and alignment, shall be monolithically attached to prefabricated F.R.P. base manhole liners to extend to the outside profile of the precast concrete structure per drawing details.
(3) The outer surface of the liner to be aggregate coated and have steel spirals/ lattice bonded to the F.R.P. to insure anchoring to concrete sections.

(1) The F.R.P. liner shall be cast integral with the precast concrete manhole base, riser and flat top/ cone sections in accordance with the liner manufacturer's specifications. The liner sections including the base liner (benching and pipe bell connections & channels greater than 12" diameter) must be fully supported during the casting process, lifting devices shall not penetrate F.R.P. liner.
(2) Inside F.R.P. liner surfaces shall be free of bulges, dents and other defects that result in a variation of inside diameter of more than 1/4" (7 mm) for base liner flow channel and pipe connections. The precast concrete section joint surfaces shall be free of excess concrete at external and internal surfaces to insure proper seal of pipe connection and F.R.P. liner.

(1)Prefabricated F.R.P. brick adjustment collar or GU F.R.P. Convertible Collar liner for masonry grade adjustment shall extend vertically to cast iron cover ring.
During the field installation of F.R.P. lined precast manhole sections, all internal seams are to be sealed per the liner manufacturer's standard method and details, to include the use of approved butyl sealant strips (ASTM C-990 Section 6.2) at internal liner joint flange. Outer joints of precast concrete sections shall be sealed as prescribed by precast manufacturer and utility specifications.
(3) After structure assembly is complete, the interior surfaces of the liner shall be completely free from pinholes, cracks, pits or defects, which are detrimental to the intended use of the liner. No F.R.P. liner shall have holes, or openings, which will permit the passage of liquid or gases through the liner wall to precast concrete. There shall be no exposed concrete mortar through inside liner surface to include (but not limited to) pipe penetrations precast section joints or cast iron cover ring joint. All mechanical anchor attachments through liner surfaces must be sealed with an approved elastomeric sealant. Consult liner manufacturer for specific information regarding approved sealant supplier list and availability.


Furnish fiberglass reinforced plastic (F.R.P.) of polyurethane hybrid polymer resin to be installed in sanitary sewer manholes and lift station/ wetwells as a protective surface barrier. The F.R.P. polyurethane hybrid polymer liner shall be a non load-bearing component, which is resistant to the chemical environment normally found in wastewater collection systems. The liner shall be prefabricated rigid F.R.P. sections of unlayered homogeneous composite with an aggregate coated outer surface to insure adequate mechanical anchoring of F.R.P. liner to concrete/ grout in sanitary sewer structures.

2.0 Materials: F.R.P. Polyurethane Hybrid Polymer Composite

2.1 Minimum Thickness:
(A) Integrally cast in new precast concrete structures Minimum thickness 3/16" (5 mm)
(B) Field installed rehab/ retrofit into existing sanitary manholes Minimum thickness 1/4" (7 mm)

2.2 Material Properties
(A) Fiberglass (Type E Glass) Minimum length of fibers = 0.625 inches Content by weight 12% - 15%
(B) Inert Filler Content by weight 10% - 13%
(C) Bonding aggregate - prewashed, kiln dried, fractured 3/8" gravel Graded particle size minimum 3/16" and maximum 3/8" Rate of application - 3.5 lb/ sq ft

2.3 Physical Properties
(A) Abrasion resistance - Falling Sand (ASTM D968) Thickness of material removed passes

Total for 25 passes
Thickness removed
.04 mil
0.04 mil
0.6 mil
0.04 mil
0.12 mil
1.2 mil

(B) Density of F.R.P. Polyurethane Hybrid Composite (ASTM D1622) - 1.17g/cm3
(C) Shore "A" Hardness Durometer (ASTM D2240) - Exceeds 90 on scale
(D) Percolation Test - Water absorption of top surface - 0.032%
(E) Thermal shock (CSA-B45-M93) 100 thermal cycles- no sign of surface defects

2.4 Chemical Resistance
(A) Chemical Resistance (Selected Reagents) (ASTM D1308)

Nitric Acid 69% No surface Degradation - Surface Staining
Hydrochloric Acid 60% No surface Degradation
Ammonia 28% No surface Degradation
Sodium Hydroxide 5.25% No surface Degradation
Sulfuric Acid 50% No surface Degradation
Sulphuric Acid 70% No surface Degradation
Sulphuric Acid 80% No surface Degradation
Acetone No surface Degradation
Unleaded Gasoline No surface Degradation
Turpentine No surface Degradation

(B) Acetone Immersion (ASTM. D2152) - No attack

NOTE: For comprehensive Precast or Rehab/ Retrofit liner specifications refer to GU Fiberglass Plastic Liner Specifications for GU F.R.P. Manhole Base Liner, GU F.R.P. Manhole Liner, GU F.R.P. Wetwell Liner and GU F.R.P. Rehab Liner.