manhole base liner shall be a FIBERGLASS REINFORCED
PLASTIC (F.R.P.) BASE LINER SYSTEM, which is resistant
to the chemical environment normally found in wastewater
transmission systems. The F.R.P. Base Liner shall be
a non-load bearing component integrally cast and adequately
anchored inside new precast concrete manhole base sections
during concrete casting process at the concrete precaster's
FIBERGLASS MANHOLE BASE LINER
(1) The prefabricated F.R.P. base liner shall be a one
piece construction of unlayered, homogenous composite
with minimum thickness shall be 1/8" (3 mm) and shall
be in lengths and nominal inside diameters corresponding
to the precast concrete base 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 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 adequate anchoring to concrete base sections
to pass vacuum test with 10" of negative pressure.
INSTALLATION IN PRECAST CONCRETE
The F.R.P. base liner shall be cast integral with the
precast concrete manhole base section in accordance
with the liner manufacturer's specifications. The liner
must be fully supported during the casting process;
lifting devices shall not penetrate inside walls F.R.P.
(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
pipe penetration 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.
FIELD ASSEMBLY AND INSPECTION PRECAST CONCRETE MANHOLE
WITH F.R.P. LINER
During the field installation of F.R.P. lined precast
manhole base sections; all pipe connections are to be
sealed per the liner manufacturer's standard method
and details. Precast concrete sections shall be sealed
as prescribed by precast manufacturer and utility specifications.
(2) The interior surfaces of the liner shall be completely
free from pinholes, cracks, pits or defects that are
detrimental to the intended use of the F.R.P. base liner.
No F.R.P. base 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. 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.