pdf - Download as PDF File .pdf), Text File .txt) or read online. IS - - Coating and wrapping of underground mild steel pipelines - Code of practice. Thumbnails Document Outline Attachments. Find: Previous. Next. LAMS. Title, Implications of reduced from NTIS, LANL URL, http:// caite.info?pdf. Local PDF, pdf.
|Language:||English, Spanish, French|
|ePub File Size:||24.37 MB|
|PDF File Size:||15.57 MB|
|Distribution:||Free* [*Regsitration Required]|
“Knowledge is such a treasure which cannot be stolen”. IS (): Coating and wrapping of underground mild steel pipelines - Code of practice [MTD 7. IS Coating and wrapping of underground mild steel pipelines - Code of practice Designator of Legally Binding Document: IS IS - Download as PDF File .pdf), Text File .txt) or read online. Indian Standards.
Ali El-Gazzar. Although such tapes are not yet very widely used in this country. Place the recei- ver under the cup. Muhammad Yousuf Memon. Primer and tape shall be furnished by the same manufacturer. Procedure for Holiday Testing. Manak Bhavan.
Blasted surfaces which rust before the priming coat has been applied should be cleaned of this superficial rust by wire brushing or emery papering at the discretion of the Engineer.
Kettles shall not be used as a continuous coating supply source by adding unmelted coating material after application temperature have been reached. If the rust formation is heavy.
Kettles shall be completely emptied of one charge and cleaned when necessary before re-charging. If the primer coat is found to be unsatisfactory. Simultaneously with the flood. Bare cables. The underside of the pipe should be inspected while lowering and any damage shall be I-epaircd before the coated pipe is lowered into the trench.
There should be approximately 0.
Any enamel which has been held in the melting kettle at application temperature for four hours or more. The pipe coating system shall depend upon the type of soil see 7. Transport facilities.
After lowering. Care shall be taken to ensure that it is at no time heated above the maximum temperature recommended.
Finished enamel lining shall be free from wrinkles. Pipe dimensions and material. The temperature of the enamel on application shall be as recommended in 5. Part II Underground For soil resistivity above 5 ohm-cm.
The coating system based upon the soil resistivity may be selected on the following basis: Thickness of Coating Suggested Test Voltage mm 2. This shall be. About 13 kg of enamel shall be broken into pieces approximately mm in maximum cross-section. The primer shall be applied with a clean flat-bristle brush of 25 mm width. The remaining enamel in the container about 9 kg shall be maintained at the specified appIication temperature for 1 hour.
All test plates prepared As specified in A-l. The enamel shall be stirred with a metal bar at intervals of 15 minutes during the heating period.
A 6 mm thick steel plate shall be interposed between the container and the gas flame to avoid superheating. One side of each plate surface. A profile of 3 mils 0. These plates shall be kept in room. Steel plates of and grease. Plates shal1 be primed and dried while laying horizontally in a well ventilated room. Immediately upon reaching the specified application temperature. The plates prepared by either method shall be stored in vertical position so that the scribed lines are horizontal in the chamber in which the temperature shall be controlled at the temperature and for the period specified for the appropriate grades in Tables 5 and 6.
The deflection producing the initial cracking shall bc recorded and deflection shall then be continued to a maximum distance of 37 mm.
Method A. At the end this period. Enamel one side in the manner previously described. Use 30 x x 5 mm plates. Scribe lines 25 mm apart across the face of the enamel surface and continue on the uncoated surface of the plate to the edges. Use x x 3 mm plates. The average of the sag of the scribed lines on two plates shall be recorded as sag of the enamel. The specimen shall then be removed from the machine for examination.
Four plates x x I. All disbonded enamel shall be removed from the plate and the area of metal exposed on the four plates shall be measured. The average initial cracking and disbonded area shall be recorded. The deflecting load shall be centrally applied across the plate by a 12 mm radius mandrel at the rate of 25 mm per minute to produce tension in the enamel until cracking occurs. Scribe three lines at 75 mm intervals across the enamel surface. After a 6-hour period.
The ball shall be dropped so as to strike the enamel at a point at least mm from the edge of the plate. After one such impact. A steel ball weighing g with a well polished spherical surface shall be dropped from a height of 2.
The same ball shall then bc dropped from a height of 2. These plates shall be allowed to cool to room temperature. Two plates of x x 12 mm shall be enamelled on one side in the manner previously described see A-l. Each plate shall bc removed front the water bath. Testing procedure as given in A After removal of loose coating. Two plates x x 3 mm shall be enamelled on one side in the manner previously described see A-l.
Each plate shall be supported on the true plane surface of a block of wood. The point of impact shall be at least mm from any edge of the plate and shall be at lcast 75 mm from the point of direct impact. After being subjected to direct impact. When the plates reach room temperature. I hrzci hirid. While being filled. Test should be completed in minutes. This shall be done as follows: The plate shall be hcatcd by immersing it for a period of approximately 3 hour in the water bath maintained at the selected temperatu: One test plate shall be tested directly.
At the end of this period. The second test plate shall be stored in a horizontal position.
At the end of each heating period. Adhesion of the cnamcl at each of the indicated test temperatures. Pour the heated sample into two rings. Coal tar pitch should be brought to the desired pouring conditions in minimum time. Cool for a minimum 30 minutes. Using forceps. Avoid the effects of drafts. Reject all tests in which the rate of rise does not fall within these limits. Allow the dish to cool to room. The rate of rise of temperature shall be uniform and shall not be taken as average over the period of the test.
Make no correction for the emergent stem pf the thermometer. Weigh to the nearest milligram between I. In case the test js repeated. The maximum permissible variation for any 1 minute period after the first three shall befO9C. AsscmhIe the apparatus with the rings.
L clean container and sample.
Heat the dish and its contents in an oven at the specified temperature for 3 hours. A stop-watch or stop-clock. A spirit level. Place the receiver under the cup.
This and the following operations shall be carried out with minimum delay to avoid loss of solvent. The time taken is recorded in seconds as time of ffow in flow cups. The cup may be at a temperature different from that of the sample and it is recommended that a minute or so be allowed to elapse before checking the temperature. Remove the finger and simultaneously start the stopwatch. Watch the stream of liquid flowing from the orifice. Gner and adjust the temperature to meet the requirements specified in 9.
Level by the use of a spirit level placed on the rim. Ml by where M1 is the mass of sample before heating. If bubbles are present. Wire cloth test sieves second revision. A suitable stand. At the first evidence of a break of the stream into droplets the stop-watch. Primer shall contain no benzol and shall not settle in the container to form a cake that cannot be mixed easily by hand stirring. It is with this idea that corrosion resistant tapes for the pipeline industry.
The principal application of these tapes are mainly limited to: Site wrapping of steel gas. It shall be a liquid that can be applied without heating and shall produce an effective bond between the surface to be protected and the subsequent.
Rolls shall be warmed on hollow course having a minimum inside diameter of 37 mm. Protection of couplings. The primer shall be allowed to dry to the touch prior to tape application.
Either single or double wraps shall be specified by the purchaser. The manufacturer shall provide assistance in demonstrating the proper method of application if requested by the contractor or purchaser. In application. Primer shall be applied by brush.
The tape shall provide a minimum thickness of I5 mils of coating between the steel surface and the inner face of the fabric when applied under the tension necessary to provide a void free wrap. In no case shall thickness of the tape be less than 1. The variation in the thickness of the tape shall not exceed f mm from the thickness specified.
Primer and tape shall be furnished by the same manufacturer. Should the tape have a plastic film separator of the type that is not removed prior to application. The standard length of tape on one roll shall be either 9. In any event. A test arca shall be selected by the inspccto: If the temperature is outside this range. This is a three-layer anti-corrosion system comprising a tough polythene film laminated to a layer of uncured synthetic rubber compound.
It is designed for application by standard methods. The system consists of the following components. A petrolatum compound coated on to. The plastic nature of the compound enables it to flow slightly under the tension applied during wrapping.
A butyl-rubber compound which is chemically inert and therefore remains unchanged by age. A layer of polythene sheeting. It is applied separately over the protective tape with staggered laps to give added strength and electrical resistance.
The soft adhesive inner layer welds together under the applied tension thus forming a continuous membrane which is impermeable to water penetration. Extremely high electrical resistance is achieved.
The polythene outer layer provides an extremely tough barrier to physical damage. Sector C. Lewis Road. Universitv P.
If air pockets are observed incision with pin or blade can be made on the air pocket area to remove entrapped air. Then entrapped air can be expelled by pressing. After removing the entrapped air it has to be repaired. If any surface crack observed it has to be repaired by slightly warming the cracked area with blow lamp and pressing. Thereafter, if necessary procedure of holiday repair to be followed.
Coated pipes shall be handled at all times with equipment such as stout, wide-belt sling and vide padded skid designed to prevent damage to coating.
Particularly for the pipes coated in site. After laying if there is any damages observed holiday test has to be done. All repair spots sections areas must be holiday tested again after repair work.
If a coated pipe remains over ground, it has to be protected against black body absorption and against ultraviolet light by using white wash or water emulsion latex paint or Kraft paper as recommended in AWWAC Any coated pipes shall not be exposed as bare coated for more than 2 days. Download pdf. Remember me on this computer. Enter the email address you signed up with and we'll email you a reset link. Need an account? Click here to sign up. Help Center Find new research papers in: