AVK 258/30 Manual

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AVK UK, 8 Rushmills, Northampton, England, UK, NN4 7YB, T: + 44 (0) 1604 601188. [email protected] www.avkuk.co.uk
COPYRIGHT©AVK GROUP A/S 2018
The designs, materials and specifications shown are subject to change without notice due to our continuing programme of product development.
O&M 090618
OPERATION AND MAINTENANCE INSTRUCTIONS
AVK FABRICATED COUPLINGS FOR WATER AND WASTEWATER
Series 258/30 and 259/30
INTRODUCTION
AVK fabricated straight and stepped couplings, for all ferrous, GRP, PVC pipes and stainless steel pipe/welded
tube suitable for use with water, waste water and neutral liquids.

2 of 3
AVK UK, 8 Rushmills, Northampton, England, UK, NN4 7YB, T: + 44 (0) 1604 601188. [email protected] www.avkuk.co.uk
COPYRIGHT©AVK GROUP A/S 2018
The designs, materials and specifications shown are subject to change without notice due to our continuing programme of product development.
O&M 090618
OPERATION AND MAINTENANCE INSTRUCTIONS
AVK FABRICATED COUPLINGS FOR WATER AND WASTEWATER
Series 258/30 and 259/30
2. HEALTH AND SAFETY PRECAUTIONS
Make sure all relevant Health and Safety issues and regulations are adhered to prior to and during installation or maintenance
work carried out on this product. It is the end user’s responsibility to ensure that safe working practices are followed at all times.
Whenever AVK’s products are installed, operated or maintained the inherent dangers of pressurised liquids and gasses must be
addressed. Before work on a valve or other piping component is undertaken, that may involve the release of internal pressure, the
valve or line must be fully isolated, depressurised and drained prior to commencing the work. FAILURE TO COMPLY WITH THIS
MAY RESULT IN SEVERE INJURY OR DEATH.
All workers handling the product must be aware of the weight of the components or assemblies to be handled and manipulated
during installation and maintenance.
It is essential that staff undertaking these operations are adequately trained and it is the responsibility of the end user that only
trained and competent staff undertake these duties.
This manual has been designed to assist, but it cannot replace quality training in the workplace. However, the AVK technical staff
is always available and ready to answer questions relating to specific problems that may not be covered by this manual.
AVK’s products are designed to be fit for purpose and to a high reliability standard. This provides a safe, low risk product when
used correctly for the purpose for which it was designed. However, this assumes that the equipment is used and maintained in
accordance with this manual, and the user is advised to study it and to make it available to all staff that may need to refer to it.
AVK cannot be held responsible for incidents arising from incorrect installation, operation or maintenance. The responsibility for
this rests wholly with the end user.
3. INSTALLATION
Checks to be made prior to installation:
1. Confirm the actual outside Diameter of pipe ends to which the fitting is to be assembled.
2. Check that the pipe ends are smooth (free from dents, weld seams and score marks etc....)
3. Ensure that the sealing areas on the pipe ends are cleaned by wire brushing removing all scale, rust, protective coating and
general debris etc...
4. Confirm that fitting to be assembled is fit for purpose with regard to type, pressure rating, sealing range, flange ratings and
medium conveyed etc...
5. Ensure that working area is sufficient to allow comfortable access and installation.
6. Check that all necessary tooling is readily available, including torque wrench, box spanners, WRc approved lubricant etc...
7. Check that fitting has not been damaged during transit / storage.
Installation:
1. Position pipe ends to be coupled, checking the level and concentricity to each other, adjust trench bed or pipe supports as
required. In the event of a spool piece being assembled it is important that independent permanent support is provided to
ensure that no external forces are imposed onto the coupling assemblies.
NOTE: In the event of backfilling the trench, adequate permanent support must be provided to the spool piece in-line with
standard working practices, taking into account nature of subsoil etc...
2. To assist centering of coupling over pipe gap, mark pipe an equal distance from each end, approx. half the fitting length plus
25mm.
3. Dismantle the fitting, ensuring that all the components are kept clean throughout installation.
4. Slide gland ring over each pipe end, with seal housing facing pipe end.
5. Lubricate sealing area on each pipe end thoroughly with an approved lubricant, then slide the sealing ring over each pipe end,
ensuring that the thick end is housed in the gland ring.
6. Position centre sleeve over pipe ends, adjusting free pipe to provide correct setting gap as listed below :
Series 258 Straight Coupling
DN 350 - DN 900 SETTING GAP = 25mm
DN1000 - DN1630 SETTING GAP = 36mm
Series 259 Stepped Coupling
DN 350 - DN 900 SETTING GAP = 25mm
DN1000 - DN1200 SETTING GAP = 36mm
NOTE: AVK couplings must be restrained properly before any end loads are applied
either longitudinally or laterally. Failure to do so will result in “pipe pull-out”.

3 of 3
AVK UK, 8 Rushmills, Northampton, England, UK, NN4 7YB, T: + 44 (0) 1604 601188. [email protected] www.avkuk.co.uk
COPYRIGHT©AVK GROUP A/S 2018
The designs, materials and specifications shown are subject to change without notice due to our continuing programme of product development.
O&M 090618
7. Line up bolt holes in each gland ring, fit all bolts from same end, ensuring that the D-neck of the bolt locates in the elongated
holes of gland ring, fit nuts and washers and tighten to finger tight.
8. Check that assembly is correctly positioned over pipe ends, then tighten diametrically opposed bolts one or two turns at a
time, to ensure that seal compression is evenly applied within the fitting. Work around the coupling until the recommended bolt
torque setting of 40NM is achieved.
9. On completion of bolt tightening, check that the coupling is still centrally positioned over pipe ends and that the gap between
the pipe and inside Dia of gland ring is even all around.
10. It is advisable to recheck the torque settings overnight of initial assembly, in case of relaxation of the sealing element.
11. Should the product be used in an aggressive (e.g. Salt laden) environment please ensure that there is sufficient secondary
corrosion protection applied before backfilling.
Possible reasons and causes of failure
OPERATION AND MAINTENANCE INSTRUCTIONS
AVK FABRICATED COUPLINGS FOR WATER AND WASTEWATER
Series 258/30 and 259/30
Correct size fitting for pipe Is pipe diameter, (average), correct for fitting size / tolerance
Is pipe diameter, (maximum & minimum (i.e. check ovality)), correct for fitting size /
tolerance
Pipes aligned to each other Max allowable angular deflection of the two pipes relative to each other is
<DN600 is ± 8°
DN700-800 is ± 6°
DN900-1200 is ± 4°
Are the two pipe centreline axis in line?
Pipe movement resulting in pipes not
being aligned.
Pipes not supported and held in line
Ground movement under pipe supports when additional weight of water and / or
ground cover applied
Fittings not assembled onto pipe
correctly
Pipe greased
Seal greased
Bolts finger tight with gland rings concentric to pipe, square to pipe and each other
Tighten bolts diametrically opposite in an even manner to keep gland ring
concentric to pipe, square to pipe and each other
Keep tightening until all fasteners 40Nm. This may involve going round many times
until they remain at 40Nm consistent
Recheck torque after leaving overnight in case of seal relaxation
Pipe surface finish Pipe not smooth (dents, weld seams, score marks)
Pipe contaminated with scale, rust, dirt, debris)
External force acting on pipe / fitting Weight of water or weight of backfill applying external force to pipe / fitting
resulting in pipe movement or pipes moving relative to each other causing angular
deflection or pipe misalignment or seal compressing more at 6 o’clock position and
reducing seal compression at 12 o’clock position
Debris Seal allowed to get contaminated with dirt / debris during installation