Valve FAQs

What do the abbreviations on the valve product pages stand for?

BS: British Standard

BSP: British standard pipe

CF: Copper alloy faced

DI: Ductile iron

DN: Nominal diameter

FBE: Fusion bonded epoxy

FF: Flat face

FLG: Flange

HW: Handwheel

ID: Internal diameter

LW: Lever weight

NRS: Non-rising stem

OS&Y: Outside screw & yoke

PCD: Pitch circle diameter

PFA: Allowable operating pressure

PN: Nominal pressure

RF: Raised face

SG: Spheroidal iron

SS: Stainless steel

STD: Standard


What is the best position for the valve?

We would always recommend a distance of five pipe diameters from any turbulence inducing component, such as an elbow, tee or pump.

What colour are T-T Flow valves?

Our valves are coated in a durable fusion bonded epoxy coating, the colour is RAL5005.

Which valve ranges are suitable accredited for potable water applications?

The following ranges are WRAS approved; Aquavault resilient seat gate valve (DN50 – DN300), Aquabrake air valve (1” – DN200) and swing check valve (DN50 – DN600).

Can a valve have a different flange drilling to its pressure rating?

Yes.  The pressure rating of the valve is cast into the body.  This is the maximum pressure the valve shell can withstand under working conditions.  However, the flange drillings could be PN6, PN10, PN16, PN25, PN40, ASA150, BS10 Table D, BS10 Table E or other.

Are there any design constraints?

Valves are designed for either clean/potable water or wastewater applications having a maximum media temperature of 70°C and maximum velocity of 3 m/s.  For valves outside of these parameters, please contact the sales office.

Can safety guards be fitted to either side of a swing check valve?

Yes.  Basic hand tools will be required.  Always relieve pipeline pressure and isolate the flow before commencing any work.

Does T-T Flow test every valve?

Each individual valve is subjected to a hydrostatic pressure test as it leaves the production line.  The body/shell is tested to 1.5 x PN and seat to 1.1 x PN.

Do you have any other questions? Please contact us on +44 (0)1630 647200 to speak to a member of T-T flow.