This document provides specifications and service life information for SMC (Sheet Moulding Compound) manhole covers. SMC is made of unsaturated polyester resin, glass fibers, calcium carbonate, and other additives. Specifications include a glass fiber content of 20%, flexural strength of 125MPa, and heat distortion temperature over 200°C. The service life of SMC manhole covers is estimated to be over 30 years due to heat and wear resistance from the surface layer composition and ability to withstand over 2 million fatigue shocks without cracking. Load ratings range from A15 which can support 1.5 tons to D400 which can support 40 tons.

1. SMC (Sheet Moulding Compound)
Specification & Service Life Information
1 SMC Manhole Cover Material
Our SMC products are made of
i) unsaturated polyester resin(UP) (Iso type resin, vinyl ester resin)
ii) unsaturated and continuous non-alkali glass fibres (E-glass 2400 Tex)
25-35%（deponds on loading and deflection）
iii) calcium carbonate 50%
iv) antioxidant 0.2%
v) firming agent 0.2%
vi) UV additive 0.2%
vii) other auxiliary materials 2%
viii) mold discharging agent 2%
ix) Low shrinkage agent 0.2%
x) Conditioning agent 0.2%
2. SMC Manhole Cover Specification
characteristics Test method Value
Quantityglass uniplast472 20%
Glass fiber length uniplast472 25mm
Linear shrinkage Uniplast408 0.12%
Density UNI 7092 1.8g/cm3
Water absorption UNI ISO 62 Met ≦0.2%
Flexuralstrength UNI EN63 125Mpa
Flexuralmodulus UNI EN63 9500MPa
Impact strength(charpy) UNI 6062 9500MPa
Rockwellhardness(Mscale) UNI 4278 80HRm
Heat distortion temperatureHDT UNI 5641 ≧200°C
Surfaceresistivity DIN 54382 ≧13
Trackingresistance IEC 112 600PTI
Glow wire GWFI(thickness3 mm) IEC 695-2-1 960°C

2. 3 The Service Life
i) From the resin heat resistance view, our products under the normal temperature
uses, its service life may amount to above for 30 years.
ii) The SMC manhole cover uses lamination compound craft on the surface layer
between 5-8mm, where it joins the antioxidant to bear the marquis resin and it is
filled by the aggregate of quartz, corundum and anti-friction materials (this kind
of material is uses for the make grinding wheel), The surface of the manhole
cover will not have any attrition because the designed 5-8mm provide wear
resisting level extrapolation, it is possible to use above for 30 years.
iii) The compound material of the manhole covers make sure that it could withstand
more than 2 million fatigue shocks. Official tests and experiments have shown
that cracks will not occur, giving it an extremely long service life.
iv) It some places where summer temperature is higher at 43℃ and the road
surface temperature reaches as high as 50~60 ℃, our Polymatrix manhole
does not show any problem on the heat resistance after more than 3
years of exposure.
v) To increase the intensity of the product, solidification craft
processing is used after normal solidification process is done.
vi) Although the resin has joined with antioxidant which will delay the
product from yellow stain, after a long period of time some yellow
stain will still appear. It is a normal condition and does not affect
the product. Our suggestion is to use color of natural stone material
where only minor color change will occur.
vii) Load ability: A15(can load 1.5ton) B125 (can load 12.5ton)
C250(can load 25ton) D400(can load 40ton)

3. According to EN124:
A15: Areas which can only be used by pedestrians and pedal cyclists
B125: Footways,pedestrian areas and comparable areas,car parking decks.
C250: For gully tops installed in the area of kerbside channels of roads which when
measured from the kerb edge,extend a maximum of 0.5m into the
carriageway and a maximum of 0.2m into the footway.
D400: carriageways of roads including pedestrian streets,hard shoulders and
parking areas,for all types of road vehicles.