15
9. Manhole risers – (deep inverts):
Manhole risers are available for deeper installation requirements
)r
250mm
manhole risers require installation suitable for the site condition.
)r
500mm* & 750mm*
manhole risers require a
complete concrete
installation – See section 10.5.
)r Max manhole riser is 750mm
Never place the covers of the
tank below ground level.
Do not allow ground water
enter the system
Only Tricel Duos manhole
risers should be used
Manhole risers are available
as standard
250mm
500mm
750mm
*Plants with a manhole riser of 500mm or 750mm must have a concrete installation. 500mm and 750mm
risers cannot be retrofitted unless the correct installation is in place.