The principle applications for flap valves are for surface water drainage associated with river, estuary and sea
water outfalls to prevent backflow into the sewer and for final effluent outfalls from wastewater treatment
works to prevent flood damage within the works.
nON-RETURN VALVES
Non return valves or backwater valves are used within sewerage and drainage systems to eliminate the risk of
flood damage by the backflow of sewage or flood water into properties through low level entries such as low
level drain gullies, toilets and washing machine outlets. The Environment Agency in their publication on
damage limitation for properties at risk from flooding and the Government guidance note “Preparing for
Floods” both recommend the installation of non-return valves (anti-flooding devices) on all such drains and
sewers.
The Building Regulations 2000, Approved Document H, recommends the installation of non-return valves on
drains from basements in low risk areas and on all drains in areas with a high risk of flooding or sewer
surcharge.
These valves are also used in commercial and industrial application where non-pressure flow control is
required (e.g. fish farming)
NON-RETURNING VALVES
REDI
DN100 to DN600 A range of PVCu non return valves complying with the requirements of BS EN 13564 - ‘Anti-flooding devices for buildings’. Sizes DN100 to DN200 are certified by the German Institute LGA.
These valves are watertight to a pressure of 0.5 bar (5m Head).
These valves have a spigot and socket with integral seal as standard for direct connection to solid walled PVCu
pipe but double spigot versions are available to special order for sizes DN400 and above. They can be
connected to other pipe material using Mission Rubber Flexible couplings (see separate technical brochure).
DN100 - 200
DN250 - 300
DN400 - 600
Single Flap with Locking Lever
Single Flap without Locking Lever
R = Stainless Steel Flap
D = Outside Diameter Spigot
NORHAM
DN250 to DN500 A range of grp non-return valves designed for connection to any pipe material using Mission Rubber
Standard Couplings and Bushes.
USES
Resistant to 1bar (10m head) back pressure
Low weight for ease of installation yet with high mechanical strength
Resistant to all normal sewage effluents operating at normal temperatures (below 80 C) and not containing harmful industrial effluents.
Seals at a low level of back pressure
Easily connected to any type of pipe material
Low maintenance
DN250
DN300 - 500
FLAP VALVES
A range of grp flap valves designed for ease of installation due to their low weight but with exceptional mechanical strength and durability.
ADVANTAGES
Resistant to 1bar (10m head) back pressure
(Multi-CD 0.8 bar)
Most sizes can be handled by one person due
to low weight
Low weight ensures ease of installation
High mechanical strength
USES
High resistance to corrosion and ultraviolet
degradation
Seals at a low level of back pressure
Low operating head due to low weight
Low maintenance
MULTI – N
DN200 to 600
A range of flap valves designed for direct
connection to any type of drain or sewer pipe using
Mission Rubber Standard Couplings and Bushes
advantages
Eliminates need for concrete headwall or pipe flange for fixing e.g. can be connected to the spigot of an outfall pipe passing through gabions
No drilling required
Fast and easy installation
MULTI – BD
DN100 to DN200 A range of small diameter flap valves with a PN 10 flange and an integral foamed EPDM rubber gasket for
direct fixing to a flange or concrete headwall.
advantages
Lightweight for fast and easy installation
No need for cement grout when
fixing to a headwall
Wall mounting kits available
MULTI – CD
DN250 to 600
A range of medium diameter flap valves with a PN 10 flange. Integral EPFM rubber sealing rings for sealing to concrete headwall.
advantages
Lightweight for fast and easy installation.
Resistant to 0.8bar (8m head) backpressure.
No need for cement grout when fixing to headwall.
Hinged design ensures full face sealing when closed.
MULTI – NB
DN200 to 1500
A range of medium diameter flap valves with an inclined flap and
PN 10 flange. Integral EPFM rubber sealing rings for sealing to
concrete headwall.
advantages
Lightweight for fast and easy installation.
Inclined flap for additional security against backflow.
No need for cement grout when fixing to headwall.
Hinged design ensures flap closure when no discharge.
TECHNICAL DATA
NORHAM FLAP VALVE TECHNICAL DATA
NOTE: PCD = PITCH CIRCLE DIAMETER OF THE BOLT HOLES
Flanges drilled to BS EN 1092 PN10 pitch circle diameter as standard except those marked in red.
Standard bolt holes in the flanges are not drilled to BS EN 1092 diameters (see table) but can be supplied to special order.
GENERAL LOCATIONS Flap valves should be fixed so as to avoid the accumulation of debris around the invert which could prevent the valve operating correctly.
TIDAL LOCATIONS Turbulaence of flow due to severe wave action will shorten the working life of a flap valve. Therefore
it is recommended that careful consideration is given to the positioning of valves and they are
installed within an outfall bay or otherwise protected from direct wave action by baffles.
Your
Order
8
Items -
£178.95
Scanprobe House, Unit 11 Bushey Close, Old Barn Lane, Kenley, Surrey
CR8 5AU Tel: 0203 253 2001