Stuart Bilby Engineers Ltd - Pukehangi

(This is a draft list - there are many more to add!)

Pipework

Adequate support, anchors

All bolts in wetwell should consider stainless steel

Backing rings stainless steel

Be careful with Denso on PE pipe can possibly soften

Care with solids velocity in vertical enlargers

Cast iron pipe maximum 1200 mm long (5.3 m DI)

Concrete blocks under valves

Counter-rotation in wetwell anticlockwise

Drop inlets

Flanges AS/NZS4087 (Class 14 usually)

Flap valve on overflow

Flexible joints on incoming lines

Flush valve

Freezing

Full face ABS flanges have no pressure rating.

Hazard zone NZS6101.1:1988

NPSH

Nylon coated valves and CI pipework

Pump drilling to match flanges

Removable pipework

Bubbles through flow meter

Flow meter flowing full

ABS plastic threaded fittings derated

ABS unions 100 mm class C only

ABS Victaulic shoulders maximum capacity 1400 kPa for 100 mm

ABS>150 mm Class D maximum

Screen or siphon on overflow

Seal around pipes

Stainless steel bolts lock up Molybond coat

Stub flanges fit in wall cast extra concrete, shear forces

Take off tee for pump out

Thermal expansion specification

Threaded fittings pressure limitations

Tideflex valves from tanks (specify pipe OD and if valves need to be eccentric) Also maximum backpressure, forward pressure and headloss

Valve and fittings support

Valve on incoming sewers

Vibration

Vortices

Wrap buried gibaults in Denso tape

Pump Well

1050 mm dia can be too narrow to work in without getting dirty for deep pump stations especially.

400 mm minimum ladder width OSH

Air entrainment cavitation at minimum water depth

Install air vent

All steelwork, brackets and pipe specials to be sandblasted and galvanised

Anchor blocks

Baffle to storage and overflow

Benching

Cabinets buildings etc keyed alike

Caisson scabbled and attached

Chains

Chamfer concrete edges

Ensure valve slamming noise doesn't irritate neighbours

Flood levels

Flotation

Flygt Tops bases should be considered

Fosroc Supercast SW as a waterstop where PE pipes pass through walls

Harness clips 15 kN

Head height for working (1.2-1.8 m minimum)

Hooks for chain, cable, floats

Inlet baffle water falls downwards from inlet pipe can miss baffle

Inlet splash air entrainment

Inlet spray onto ladder

Ladder away from inlet splash, near control cubicle

Ladder better than rungs

Ladder doesn't clash with pumps (really!)

Ladder on caisson step rungs obstruct clam-shell

Ladder or pole to grab above surface

Ladder top rung high, handles on getting out

Lid hole and pump location dimensioned

Location of existing pipes on existing pump stations

Manhole rungs should be on downstream side nearest road. (least chance of new incoming lines)

No surface water flowing into lid

Overflow from subsidiary manhole with valves to allow wetwell to be worked on

Overflow pipe diameter

Paint Devshield worth considering

PE rungs option in corrosive area

Pump labels

Pump spacing centres at least 2.1 x square root of flow in m³/s

Safety rungs (300 centres)

Schedule manhole water test

Site all-weather vehicle access

Stainless steel hold down bolts detail

Standard services disclaimer note

Tripod setup

Ultrasonic beam cone angle

Valve chamber ball valve on drain line

Valve chamber drain threaded plug, not under pipe, vertical pipe as handle

Valve chamber flotation

Valve chamber plug to prevent flooding with string

Vehicle access

Vehicle loadings

Water sprays for washdown

Water supply

Rising Main

Adequate cover to air valves label on long section

Adequate velocity (1-1.07 m/s for raw sewage) or check using tractive force method

Air bubble velocity rising main

Air inlet valves can cause water hammer as well

Air release valves odour, noise

Air release valves suck air in bubbles

Allow for build-up of deposits on pipe in treatment plant.

Anchor blocks

Can jet pipeline 160 m (250 m maximum)

Check for collapse under negative pressures

Class B uPVC can collapse under vacuum

Drain rising main

Locator tape (300 to 600 mm below surface)

Traceable marker tape for plastic pipe

No siphoning

Odour, retention time, sulphuric acid build-up

PE flanges, stainless steel, weld, smooth bore reducers 8° taper

Pipe collapse low pressure, external loads

Schedule destructive testing

Seepage cut-off collars

Specify source of water for testing.

Standard services disclaimer note

Water hammer including start-up