S1904-1_CLEANLINESS_REQUIREMENTS_FOR_HYDRAULIC_PIPING_SYSTEMS.pdf

August, 1994

NOAA Standard Specification - S1904-1

CLEANLINESS REQUIREMENTS FOR HYDRAULIC PIPING SYSTEMS

1. SCOPE

New hydraulic piping systems and repaired or modified existing hydraulic piping systems shall conform to this specification.

2. GENERAL REQUIREMENTS FOR CLEANLINESS

2.1 New Piping: All new pipe and fittings such as welded or brazed elbows and flanges, shall be thoroughly deburred, cleaned and pickled prior to final installation in the system. Cleaning and pickling shall conform to paragraphs (3) and (4) respectively. For "Fit-Up" purposes, new pipe sections may be initially installed without cleaning or pickling, providing that these pipe sections have been deburred on the ends and flushed or blown out to insure that loose particles will not fall into existing installed pipe sections, or other system components. After "Fit-Up" has been completed, the new pipe and fittings shall be removed, cleaned and pickled. Under no condition, shall oil be circulated through new pipe and fittings when installed in the system, until deburring, cleaning and pickling has been completed. After cleaning and pickling has been completed, pipe ends shall be capped until installed in the system. No further burning, cutting or welding will be permitted on cleaned and pickled piping.

2.1.1 In place cleaning and pickling of new system pipe will be authorized on a case basis subject to approval of the government representative. All components subject to damage such as pumps, motors, valves, etc., shall be jumpered prior to circulating cleaning and pickling solutions.

2.2 Existing Piping: All existing piping sections that are to be burned, cut or welded, shall be removed from the system and treated as a "new pipe section", with fit-up, cleaning and pickling requirements as in 2.1 above. All existing piping connections that are opened for removal of equipment, shall be adequately capped to prevent entry of foreign matter, while system components are being repaired.

2.2.1 In place cleaning and pickling of new pipe installed in an existing system will be authorized on a case basis subject to the approval of the government representative. All components subject to damage such as pumps, motors, valves, etc., shall be jumpered prior to circulating, cleaning and pickling solutions.

Cleanliness Requirements for Hydraulic Piping Systems

S1904-1

2.3 Flushing

2.3.1 New Hydraulic System Installations: (i.e., new pipe, fittings, components, tanks, etc.) Flushing shall be as follows:

Piping shall be flushed by installing temporary jumpers around each component. A temporary pump and temporary strainer shall be installed in the system. The strainer shall be of a 10 micron mesh replaceable element type with a pressure drop not to exceed the tolerances of the manufacturer at the flow and temperature for the type fluid used. Hydraulic fluid of the same type to be installed in the system shall be circulated until no appreciable quantity of soil is deposited on the strainers. The filter element shall be checked and replaced whenever the pressure drop reaches the limits specified. The system shall be drained, the jumpers, temporary strainers and pump shall be removed and the piping assembly connected to all components, after flushing is completed.

2.3.2 Modified or Repaired Hydraulic Systems: Flushing shall not normally be required unless specifically called for by the work item or unless there is reasonable evidence to show that the Contractor has not taken precautions to prevent entry of foreign matter into the piping system.

3. CLEANING METHOD

Pipe sections shall be cleaned as follows in preparation for pickling:

a. Wire brush interior and exterior.

b. Submerge in a hot lye or tri-sodium phosphate (or equivalent) solution for approximately 15 minutes, followed by a water rinse. Dry and cap pipe unless pickling follows immediately.

4. PICKLING

Pickling shall be comparable to methods used by commercial electro-plating/pickling companies, and in general, piping pickled by commercial pickling companies is acceptable. The following procedures, or an approved equivalent, are acceptable, when pickling is accomplished by the Contractor:

4.1 Bronze, Copper and Copper-Nickel:

a. Pickle free from scale in solution of the following composition at room temperature:

Sulfuric acid, 66° Baume, sp.gr. 1.83, conforming to Type 1, Class 1 of

0-S-809 . . . . . . . . . . . . . . . 7-14 fl. oz.

Water . . . . . . . . . . . . . . . . 1 gallon

(Caution. The acid shall always be added carefully to the water.)

NOTE: If red stains appear, immerse the work briefly in a solution formulated as above but which contains in addition 2-4 oz. of sodium dichromate (per gallon) conforming to 0-S-595. This solution shall be maintained at a temperature range of 70° to 120°F.

4.2 Monel:

a. Pickle for 20 to 40 minutes in a hot solution (180°

± 10°F) of the following composition:

Hydrochloric acid, 20° Baume, sp. gr. 1.16

(See O-H-765). . . . . . . . . . 1/2 gallon

Cupric Chloride. . . . . . . . . 4 ounces

Water. . . . . . . . . . . . . . 1 gallon

b. Rinse in hot water.

c. Immerse for 5 to 10 minutes in a bath composed as follows (temperature 70° to 100°F).

Sulfuric acid, 66°, Baume, sp.gr. 1.83 conforming to type 1, Class 1 of O-S-809 . . . . . . . 13 fl. oz.

Sodium Dichromate (See O-S-595) . 17 1/2 oz.

Water . . . . . . . . . . . . . . 1 gallon

4.3 Ferrous Steel Other Than CRES:

a. Pickle free from rust and scale in a hot solution (150° ± 10°F) of the following composition:

Sulfuric acid, 66°, Baume, sp.gr. 1.83 conforming to type 1, Class 1 of O-S-809 . . . . . . . 7-14 fl. oz.

Inhibitor (see O-I-501) . . . . . Quantity recommended by manufacturer

4.4 Corrosion Resistant Steel:

a. Immerse work for 10 to 15 minutes in a hot solution (130° ± 10°F) of the following composition:

Nitric Acid (See O-N-350) . . . . 13-20 fl. oz.

Hydrofluoric Acid (60%)

(See O-H-795) . . . . . . . . . 1-2 fl. oz.

b. Rinse in a clean, warm water bath.

c. If hydrostatic test is to be performed with hydraulic oil (see 3.3.14), dry the piping assembly with clean air.

5. TREATMENT FOLLOWING PICKLING

a. Immediately after pickling, rinse in a clean, warm water bath.

b. Neutralize traces of acid from the pickling operation by rinsing the work in an alkaline bath containing four (4) ounces (per gallon of water) of soda ash conforming to O-S-571.

c. Rinse thoroughly in fresh, warm water.

d. Dry and cap.