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CHECK LIST ACCESS FITTINGS

The downstream access fittings should be situated sufficiently downstream the

injection Access Fittings by typically 5-10 pipeline diameters that adequate dispersion

of the corrosion inhibitor would have occurred by the time the treated fluid reaches the

monitoring location.For water pipelines three access fittings shall be installed. This provides an additional

access point for the installation of bio probes.

All new corrosion monitoring access fitting shall be installed at the 6 oclock position in

pipelines and network piping.

The access fitting contains the system pressure through a sequence of elastomeric

seals comprising a primary chevron-type seal and a secondary O-ring seal. The

materials for these seals must be suitable for the temperature of the proposed service.

When a new Access Fittings is installed it will be sealed with a solid plug to prevent

damage to internal threads and sealing faces and permit hydro testing of the system.

This generally requires an 1830 mm (6-ft) clearance in a direct line along the axis ofthe access fitting from the bottom of the pipe and adequate room for maneuver on at

least one side of a pipe, a minimum of 1000 mm (3.3ft) should be allowed.

Access to the fittings may require provision of detachable sections of gratings,

provision of local stepladders, modification to pipe work or walkways. An assumption

that scaffolding can be provided is not acceptable for new plant design.

ADMA-OPCO requires flare weld 2 system fittings unless otherwise specified. The flare

weld access fittings are rated to 6,000 psig.

Access into the pipe for the corrosion monitoring coupons or probes is afforded by

trepanning a hole through the pipe wall within the access fitting. It is most important

that this hole is of the correct dimensions to permit installation of the 2-inch probesand fittings. Whatever the installation method the hole shall be post reamed with a

1.375-inch (35 mm) tool after the fitting is installed.

For new access fitting installations steel thread protector caps with hole shall be used

to protect the external threads during transport and installation of spool pieces and

later during final completion of new works. Heavy-duty protective covers are not

required. These caps should be painted to BS 4800 shade 12 E 51 or equivalent.

After installation of new Access Fittings, the permanent cap will be a steel heavy-duty

protective cover complete with bleed valve and pressure gauge.

Chemical injection points should be installed on the top of the line wherever possible.

The tee pipe to the access fitting must be of minimum 1-inch diameter and fabricatedin steel of a schedule adequate for the design pressure of the system and the external

mechanical and thermal loads, which may be imposed.

The tee should be as short as is practicable but the length of the tee should not be less

than 4-inches (100 mm) to permit Access Fittings of the isolation valve. Longer tees

are acceptable but may require support to prevent mechanical damage.

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Often the bolts or studs and nuts used to fix the

permanent isolating valve interfere with installation of

the retriever valve and prevent retrieval of the injection

device in the access fitting. The length of the tee and

studs and nuts should be such that there is a clear 3.25-

inch between the body of the access fitting and the

upper bolts/studs/nuts. The area of concern is shown in

Figure - 2.

The tee pipe of the chemical injection Access Fittings should be orientated along the

length of the spool piece or pipeline to reduce the risk of accidental mechanical

damage.

No chemical injection Access Fittings should be within 75mm (3inch) of any other

weldment.

Adequate access is required for insertion and removal of internal fittings into injection

points. The space needed to install and remove the retriever is 6 ft (1830 mm)

measured from the surface of the pipeline. Clear access to one side of the pipe of aminimum of 1020 mm (40 inches) is also required.