Hawkeye PE Fittings User Manual

Technical Bulletin TB-0408-FP

Fabricated Fitting Butt Fusion Procedure

1.0 Introduction

This document provides the general recommended practice and procedures for butt fusing Hawkeye Industries’ fabricated
polyethylene fittings, including the polyethylene portion of transition fittings, to a polyethylene pipe system. It is intended for use
with Hawkeye’s PE3408 and PE4710 / PE 100 fabricated high-density polyethylene fittings. This draft document will be updated as
information is available.

2.0 Reference Documents

This procedure makes reference, directly or implied, from the
following documents:

ASTM D 2657

Standard Practice for Heat Fusion Joining of Polyolefin Pipe
and Fittings

CSA Z662-07

Oil and Gas Pipeline Systems

ERCB Directive 022 (Formerly EUB Directive 022)

Use of Bimodal High-Density Polyethylene Pipe in Oil and Gas
Service

PPI TR-33/2006

Generic Butt Fusion Joining Procedure for Field Joining of
Polyethylene Pipe

PPI TN-13/2007

General Guidelines for Butt, Saddle, and Socket Fusion of
Unlike Polyethylene Pipes and Fittings

PPI Handbook of Polyethylene Pipe, 1st Ed.

Chapter 9: Polyethylene Joining Procedures

3.0 Regulations

Read and follow stipulated fusion regulations specified by the
local jurisdictional authority.

3.1 Canadian Regulations

Refer to ERCB Directive 022 and CSA Z662-07, Sections

12.7.7.1 through 12.7.9.2.

3.2 US Regulations

Refer to US DOT Title 49 CFR Part 192.

4.0 Precautions

4.1 Connection Method

Hawkeye Industries’ fabricated polyethylene fittings shall only
be joined to a polyethylene pipe system by the heat fusion,
including butt, socket and electrofusion. Threading, solvent
bonding, hot-air or hot-gas welding, or extrusion welding
techniques, or any other method not explicitly defined as heat
fusion, are not permissible for pressure service. This
document covers only joining by butt fusion at this time.

4.2 Personnel Qualification

It is imperative that persons joining polyethylene pipe by heat
fusion are trained and qualified in the operation of fusion
equipment. Proof of qualification may be required in some
jurisdictions.

4.3 Fusing unlike PE Materials

Fittings fabricated from HDPE Material are fusion compatible
with like-designated resins, regardless of manufacturer. (i.e.
Hawkeye’s PE3408 fittings can be fused to any
manufacturers PE3408 pipe).

Fusing unlike HDPE resins (i.e. PE3408 to PE4710) can
result in satisfactory fusion joints. Refer to PPI Document TN­13 for guidelines on fusing materials with unlike melt flow
properties. The standard PE100/PE4710 Material used by
Hawkeye Industries has a melt index of 0.6 g/10 min.

For joints where 800 psi Hydrostatic Design Stress (HDS)
material (i.e. PE3408, PE3608) is joined to 1000 psi material
(i.e. PE4710) the, pressure rating of the joint will be the same
as the lower-strength material. For this reason, Hawkeye
Industries recommends that PE3408/3608/3708 fabricated
fittings not be used on PE4710 or PE100 pipe systems.
However, PE4710 / PE100 fittings are still acceptable for use
on PE3408/3608/3708 systems.

4.4 Hydrocarbon Permeation

Polyethylene pipe and fittings can be affected by liquid
hydrocarbon (LHC) contamination. When present, LHC
permeates the polyethylene which makes joining by heat
fusion inappropriate. Fusions made with LHC contaminated
polyethylene may be weak and unreliable, and shall not be
allowed into service. Contamination can stem from either
LHC in the pipeline or fitting, or from LHC leeching from
contaminated soil around the pipeline or fitting.

LHC contamination is only a factor when performing heat
fusions. The presence of LHC does not have a negative
impact on the performance of the polyethylene pipeline or
fitting once in service.

4.5 Handling

Care must be taken when handling fabricated fittings to avoid
damage to the fusion surfaces, or the OD of the fitting.
Gouging the OD of the fitting can have a deleterious effect on
pressure rating, and damaged fittings should not be placed
into service. Do not drop fittings from any height.

Steps should be taken to minimize the installation force on y­lateral fittings to prevent “wishboning.”

5.0 Fusion Preparation

5.1 Inspection

Inspect the fusion area and the outside surface of the pipe
for unacceptable damage (cuts, deep scratches, gouges,
etc.). Do not use damaged fittings or pipe.

©2008 Hawkeye Industries Inc. All Rights Reserved.
This document is for reference only and is subject to change without notice. Hawkeye Industries Inc. has made every reasonable effort to ensure accuracy, but this document may not include all special
situations or novel applications. Do not use the data provided in this document for any design or engineering purposes. Refer to applicable standards and jurisdictionally authorized publications for any and
all pressure calculations; this document is only a guide. Any information released prior to this revision is obsolete.

Hawkeye Industries Inc. TB-0308-FF

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F

5.2 End Preparation

Ensure that the free end of the pipe does not have any
necking or toe-in. The machined fusion ends of the
fabricated fitting should be free of any deformation, and
should conform to ASTM D 2513 dimensions.

5.3 Cleaning

Use only clean, dry and lint-free non-synthetic cloths for
cleaning fusion surfaces, and areas where fusion equipment
will be secured. Isopropyl alcohol may be used to clean
fusion surfaces. Do not touch or otherwise contaminate
fusion surfaces after cleaning.

5.4 Equipment

Ensure that all fusion equipment is properly calibrated and in
suitable working order. Ensure equipment has adequate fuel
prior to initiating the fusion process.

Use a pyrometer or IR thermometer to double check the
temperature of the heater several times throughout the day.

Use only collets, clamps and equipment designed for the size
of pipe, and for the type of fusion performed. Do not use
excessive force to clamp pipe or fittings.

5.5 Cold-weather Fusion

Fusion in cold weather may affect the fusion parameters. Be
sure to check and test the fusion process in cold weather to
guard against unsatisfactory joints.

Ensure the fusion area and equipment is sheltered from
wind, as well as precipitation and other sources of moisture.
Scrape off any accumulated snow or ice from the fusion area
before starting fusion.

Cold temperature can affect the dimensional and mechanical
properties of polyethylene. Slight OD contraction is possible,
although typically compensated for by fusion equipment.
Polyethylene may have increased stiffness and less
resistance to impact, so increased caution when handling in
cold weather conditions is advised.

5.6 Trial Fusion

Perform trial fusions at least once per day per size of fusion
to requalify the fusion procedure and parameters (See 7.0).
Multiple trial fusions may be required throughout the day if
weather conditions are changing.

6.0 Fusion Procedure

Throughout this section, the terms ‘force’ and ‘pressure’ may
be used interchangeably to describe the force between the
pipe ends, the facing tool and the heater. This does not refer
to the hydraulic pressure of the fusion machine. Be sure to
follow the guidelines of the fusion machine to calculate the
appropriate hydraulic pressures required to attain the fusion
forces / fusion interfacial pressures as described here.

6.1 Initial Parameters and Start-Points

The following values provide a suitable starting point for
setting fusion parameters. These shall be adjusted until a
suitable fused joint can be reliably attained via qualifying
fusion.

Heater Temperature: 210±10 °C [410±18 °F]
Interfacial Pressure: 60 – 90 psi [415 kPa – 620 kPa]
Drag Pressure: Variable - set per fusion
Cooling time: 30 – 90 sec /in pipe diameter

Regardless of fusion parameters, the cycle is split roughly
into two parts, heating and cooling.

Figure 6.1 The Fusion Cycle

In Figure 6.1, the heating portion includes the initial melt,
and the bead formation areas. Cooling beings immediately
after the heater is removed, the pipe ends are joined.

The interfacial pressure is used to determine the required
force, F
successful fusion.

Where: P
OD = Actual Pipe OD [in]
SDR = pipe standard dimension ratio
π =3.1415

If the cylinder area, A
the hydraulic pressure required (P
following:

Do not omit the drag pressure, P
required hydraulic pressure. Drag pressures for longer length
of pipe, or pipe made less flexible in cold weather can be on
the order of several hundred psi. Measure the drag pressure
for every fusion joint by noting the minimum required
hydraulic system pressure to move the fusion machine
carriage.

, between the pipe and fitting to ensure a

FUSION

SDR

⎛

2

⋅⋅=⋅=

π

ODPAPF

INTPIPEINTFUSION

= Interfacial Pressure [psi]

INT

, of the fusion equipment is known,

CYL

P += [psi]

HYD

FUSION

A

P

CYL

⎜

SDR

⎝

) can be found via the

HYD

DRAG

when calculating the

DRAG

1

⎞

[lbf]

⎟

2

⎠

2/5 Hawkeye Industries Inc. Technical Bulletin: FPR IDC and NIDC Fittings