FIELD FLARING OF PIPE SPOOLS - PTFE Lined Piping

PRODUCT DATA SHEET ES1050
FIELD FLARING OF PIPE SPOOLS USING
A SLIDING FIT LINER SYSTEM Date 12/99 Issue

Sheet 1 of 11 3

INTRODUCTION

Field flaring has become an established method of providing a speedy on site replacement service for
damaged spools or alternatively a means of manufacturing on-site closing spools. CRP provides both
a comprehensive range of spools suitable for field flare and toolkits suitable for the flaring activity.
CRP is also able to provide training and certification of site personnel when required.

PRODUCT RANGE

CRP’s standard pipe spool for field flaring is supplied in 25mm, 40mm, 50mm, 80mm and 100mm
nominal bore. The tube is supplied in lengths up to 3m in 100mm increments, with an additional
100mm of steel tube and 200mm of liner. The additional tube length protects the additional liner for
subsequent flaring purposes if the full customer pipe
spool length is required. The protruding 100mm of liner
holds the sliding fit liner in place, preventing it from
movement in storage and is discarded in use. 3m
lengths are generally provided as a stock item for
maintenance work using field flare techniques. The pipe
spools are factory finished with a 75µ coat of red-brown
zinc phosphate primer.

The standard spool design recommended for field flare
has a factory fitted rotating flange – stub welded and free
to rotate, with the pipe spool liner finished flared and
capped for transit protection. The other end is plain and
fitted with a flange suitable for welding and tack welded
into position to prevent loss in transit. This standard has
the CRP product reference ES1038.

Other popular variants include:

• ES1048 No Flanges - A pipe supplied without flanges, for use with companion flanges which
are either slip on welding or threaded.

• ES1051 Vanstone – A pipe spool supplied with a Vanstone rotating flange one end, finished
flared. The other end is plain and fitted with a flange suitable for welding and tack welded into
position to prevent loss in transit.

STORAGE

If the pipe spool is to be stored, either before or after field flaring, it must be stored in cool dry clean
conditions - ideally indoors and certainly away from direct sunlight or other heat sources such as
steam pipes, radiators or warm floors. When the liner is removed from the steel tube it must be stored
carefully to avoid sunlight or other heat sources and mechanical damage.

Tel: 01444 870504 Fax: 01444 870516

e-mail: enquiry @crp.co.uk

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PRODUCT DATA SHEET ES1050
FIELD FLARING OF PIPE SPOOLS USING
A SLIDING FIT LINER SYSTEM Date 12/99 Issue

CRITICAL POINTS Sheet 2 of 11 3

There are certain pipe spool features than can be affected by field flaring and these must be
considered when working.

Vent Holes

The tube comes pre-supplied with a number of 3mm diameter vent holes, 100mm from each end and
at 900mm intervals in between. The presence of at least one of these holes in any finished field
manufactured pipe spool is critical. Likewise, it is critical that these holes are kept clear, if overcoating
the pipe spool with paint. The absence of an adequate vent hole can cause the catastrophic collapse
of the pipe spool liner.

Spool Liner

The purpose of the sliding fit pipe spool liner is to enable it to be moved away from the working point, it
is critical not to damage the liner whilst at work either mechanically or by subjecting it to heat (other
than when flaring).

FIELD FLARING EQUIPMENT

CRP Supplied Equipment

The field flare equipment supplied by CRP is provided by NB size in 25mm, 40mm, 50mm, 80mm and
100mm. The equipment is similar in construction for each size and comprises the following:

Item Description
1 Expanding mandrel
2 PTFE ring gauge
3 Driving plug
4 Flaring head
5 Flare head drive nut & washer
6 Spindle
7 Drive Bolt
8 Socket wrench

4 1
8

56

7
23

Tel: 01444 870504 Fax: 01444 870516

e-mail: enquiry @crp.co.uk

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PRODUCT DATA SHEET ES1050
FIELD FLARING OF PIPE SPOOLS USING
A SLIDING FIT LINER SYSTEM Date 12/99 Issue

Sheet 3 of 11 3

Other Equipment Required

Before starting work assemble the equipment in the following diagram together with a suitable heat
source – propane torch, gas ring, electric plate heater or oven. The working environment should be
warm and dry and a suitable bench or trestles will be required for presenting the spool for work.

3 5 Item Description
4 6 1 Heat resisting gloves
2 Marker pen
9 7 3 Hacksaw
1 12 4 Adjustable spanner
11 5 10mm spanner
2 10 6 Half round file
8 7 Silicone spray
8 Roofing bolts
9 Hammer
10 End board
11 6mm x150mm bar
12 Probe thermometer

FLANGE ADDITION

Welded Flange (One flange)

1. Cut the protruding excess liner cleanly
at the plain end of the tube.

2. Using a hammer with the drive plug
and bolt, knock the liner free, store
carefully.

Tel: 01444 870504 Fax: 01444 870516

e-mail: enquiry @crp.co.uk

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PRODUCT DATA SHEET ES1050

Date 3/99 Issue

Sheet 4 of 11 1

3. Measure the required length of tube by
measuring from the existing flange
face the required finished length less
6mm (the total thickness of the finished
liner flanges) and an allowance for the
internal fillet weld.

4. Cut the tube to the required length,
making sure that the cut is square to
the axis of the tube.

5. File the bore removing all burrs.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

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PRODUCT DATA SHEET ES1050

Date 3/99 Issue

Sheet 5 of 11 1

6. Check that there are vent holes in the

finished tube length. If not, drill two

3mm holes centrally along the length of
the tube 180o apart for tube lengths up

to 300mm. Above these lengths drill
two pairs of holes 180o apart 100mm in

from each end of the tube, with one
pair rotated 90o to the other pair.

Deburr the vent holes internally and

externally.

7. Using the slip on welding flange
supplied, weld the flange to the plain
tube end in accordance with good
welding practice. Overfill the internal
fillet weld to allow for the provision of
the radius as in the table below. Clean
the weld to have a good flat mating
face and ensure the internal radius is
as the following table.

Nominal Bore (mm) 25 40 50 80 100

Minimum Internal Flange Radius (mm) 3.5 3.5 4.0 5.5 6.0

8. Clean all weld spatter or other debris
from within the tube

9. Refit the liner as soon as possible (to
avoid the liner tightening up). Cut this
to the required length beyond the tube
end using the PTFE ring gauge or if
not available as in the following table.
Ensure the cut face is clean and free of
tears - a rough finish could lead to
splitting during the flaring operation.

Nominal Bore (mm) 25 40 50 80 100

Liner beyond flange end (mm) 21 24 30 30 33

10. Proceed with flaring.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

20/92

PRODUCT DATA SHEET ES1050

Welded Flange (Two flanges) Date 3/99 Issue

20/92 Sheet 6 of 11 1

10. Proceed as above, but measure the
required length of steel tube by taking
the face to face measurement of the
gap, subtracting two flare thickness’
(i.e. 6mm) and two internal fillet weld
allowances. Cut the steel tube to
length, clean and deburr as required.

11. Check that there are vent holes in the

cut length of steel tube. If vent holes

are not present, drill two 3mm holes

centrally along the length of the tube
180o apart for tube lengths up to

300mm. Above this length, drill two
pairs of holes 180o apart 100mm in

from each end of the tube with one pair
rotated 90o to the other pair. Deburr

the vent holes externally and internally.

12. Weld both flanges into position taking
care to set the flanges square to the
tube axis and ensure the fabricated
length is equal to the fitting gap less
6mm (see 2 above). Overfill the
internal fillet to allow for the provision
of a radius as below. Clean the weld to
have a good flat mating face and
ensure the internal radius is as the
following table.

Nominal Bore (mm) 25 40 50 80 100

Minimum Internal Flange Radius (mm) 3.5 3.5 4.0 5.5 6.0

13. Clean all weld spatter or other debris
from within the steel tube and the
flange faces.

14. Reintroduce the PTFE liner and set
one end to the required flaring length
as shown in the following table.

Nominal Bore (mm) 25 40 50 80 100

Liner beyond flange end (mm) 21 24 30 30 33

15. Proceed with flaring the first end before
cutting the other end – as this provides
the opportunity to remake the first flare
if you have problems. Then cut the
other end again using the above table
and proceed with flaring.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

PRODUCT DATA SHEET ES1050

FLANGE ADDITION Date 3/99 Issue

Threaded Flange (One flange) Sheet 7 of 11 1

20/92 1. Cut the protruding excess liner cleanly at
the plain end of the tube and remove the
liner and store carefully.

2. Fit the tube into the chuck of a pipe-
threading machine. Measure the tube
from the existing flange face to the cut
as the required finished length less
12mm.

3. Make sure that the cut is square to the
axis of the tube and the bore is clean
and free of burrs. Cut a BSP taper
thread slightly longer than the thread on
the companion flange.

4. Remove from the threading machine and
clamp the tube in a vice. Check again
for burrs or sharp edges.

5. Fit a companion flange and tighten onto
the tube. Additional leverage can be
obtained by fitting two bolts to the flange
bolt holes.

6. Ensure the cut face of the liner is clean
and free of tears, otherwise it will split
when flared.

7. Check that there are vent holes in the
finished pipe spool length. If not drill two
3mm holes centrally along the length of
the spool 180o apart for a length up to
300mm. Above this length drill two pairs
of holes 180o apart 100mm in from each
end of the tube with one pair rotated 90o
to the other pair. Deburr the vent holes
externally and internally.

8. Refit the liner as soon as possible (to
avoid the liner tightening up). Cut this to
the required length beyond the tube end
using the PTFE ring gauge or if not
available as in the following table.
Ensure the cut face is clean and free of
tears - a rough finish could lead to
splitting during the flaring operation.

Nominal Bore (mm) 25 40 50 80 100

Liner beyond flange end (mm) 21 24 30 30 33

9. Proceed with flaring.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

PRODUCT DATA SHEET ES1050

FLANGE ADDITION Date 3/99 Issue

Threaded Flange (Two flanges) Sheet 8 of 11 1

1. Cut the protruding excess liner cleanly
at the plain end of the tube and
remove the liner and store carefully.

2. Flange the first end of the tube as
above – excepting the requirement to
determine the finished length. Then
proceed as above from the section
“Measure the tube from the existing
flange face to the cut as required
finished length less 12mm.”

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

20/92

PRODUCT DATA SHEET ES1050

FIELD FLARE Date 3/99 Issue

Sheet 9 of 11 1

1. Assemble the equipment as described
above, both CRP and own equipment.

2. Lubricate the driving nuts if necessary
with a high temperature lubricant.

3. It is critical to keep lubricant off the
clamping cones and rubber rings to get
the maximum grip during flaring.

4. Introduce the expanding mandrel into
the pipe spool bore. Slide the socket
wrench over the spindle to locate over
the nut on the end of the expanding
mandrel.

5. Push the socket wrench and
expanding mandrel into the bore until
the marked line on the socket wrench
aligns with the protruding liner.

6. Insert the 6mm x 150mm bar through
the hole in the spindle end, hold still
and tighten the socket wrench onto the
expanding mandrel. Tighten until a
solid fit is obtained.

7. Fit the probe thermometer into the

flaring head and gently heat the flaring
head until approx. 320o C is reached.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

20/92

PRODUCT DATA SHEET ES1050

Date 3/99 Issue

Sheet 10 of 11 1

8. When using a flame always heat from
the taper side and keep the flame
moving to avoid hot spots.

9. When the temperature has been
reached lubricate lightly the tapered
face of the flaring head. (NB do this
well away from the expanding mandrel,
as any lubricant on this component will
cause it to slip.)

10. Using the heat resistant gloves remove
the flare tools from the heat source and
slide the flare head over the mandrel
spindle.

11. Using the heat resistant gloves fit the
flare head drive nut and washer.

12. Slowly tighten using the socket
wrench. Light hand pressure is
sufficient. If any resistance is felt
reduce the pressure and speed of
flaring to allow heat from the tool to
soak into the PTFE and soften the
liner.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

20/92

PRODUCT DATA SHEET ES1050

Date 3/99 Issue

Sheet 11 of 11 1

13. Continue tightening until the flare is
fully formed and the flare head nose
has bottomed on the flange radii.

14. Allow the flare to cool to room
temperature with the flaring head in
position or quench in water for at least
1 minute per 25mm of bore. The flare
can be used in this condition. As an
option a flat flare can be achieved as
follows.

15. To flatten the flare repeat the above
procedure using the flat side of the
flare head and leave in position for at
least 5 minutes for the heat to soak
into the liner. Then air cool or water
quench as previously.

16. Remove the tooling examine the flare
and spark test to 25KV DC and
pressure test to at least 1.5 times the
proposed working pressure to a
maximum of 29 Bar g.

17. Fit protective end boards or install
immediately.

18. If subsequently painting the pipe spool,
it is critical not to block the vent holes.

19. To make two flares produce the first
flare as above, fitting an end board.

20. When satisfied that the first flare is
acceptable, cut off the excess liner for
the second flare using the PTFE ring
gauge or as shown in the table above.

21. If the first flare is unsuitable, then cut
off the defective flare and pass more
liner through the tube to leave the
correct amount exposed for
satisfactory flaring as in the table
above.

Tel: 01444 870504 Fax: 01444 870516
e-mail: enquiry @crp.co.uk

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