1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. SABS 0120 : Part 5 Section U-1981 Cable ducts PART 5 : CONTRACT ADMINISTIWSION SECTION LC CONTENTS Clause Page Number . STAKJ 01 CONSTRUCTION I Instructi
4、ons to Cormence Work I 1I.DIEDlATELY AFTEK TllE HANDING OVER OF THE SITE . 1 Location of Ducts/Cables . 1 DURING CONSTRUCTION 1 Administration . I . Preliminary planning 1 Program of construction I Construction Methods . I Trenching I Laying of pipes l Jointing of pipes 2 (IUALIlY CUNTKOL AND OTHEK
5、CONSIDERITIONS . 2 General 2 IJisputes, Mediations, Arbitrations, and Court Cases 2 Drawing LC-5.1 - Joining Pitch-Impregnated Fibre Pipes 3 November 1981 Approved by the COUNCIL OF THE SOUTH AFRICAN BUREAU OF STANDN(DS SARS 0120 : Part 5 Section LC-1981 Cable ducts NOTE: The clause number(s) given
6、at the beginning or arter tllv heading of a clause is/are. unless otherwise stated, the numher(s) of the relevant clause(s) of SARS 1200 LC. START OF CONSTRUCTION INSCRUCPLONS TO COMMENCE WORK. For the purposes of this part of the code, contract ndministration starts with instructions to the contrac
7、tor to commence work as set out in Sobclause 4.1 of Scct Con 0. IMNEI)LATELY AFrER THE HANDING OVER OF THE SITE LOCATION OF UUCTSfCARLKS. The engineer should ensure that the contractor knows the exact location in which ducts must be constructed and cables laid and also the date on which the work is
8、expected to commence. DURING CONSTRUCTION Preliminary Planning. The contractor should appreciate tlmt lead time may he required by the manufac- turer or the GPO, as applicable, for the supply of large quantities of pipes. A responsible person should always be on hand at the oCE-loading site to check
9、 and endorse each weighbill or delivery note. Program of Construction. The engineer should ensure that all parties involved are aware of changes in the actual program of constructLon so as to avoid situations siwh as the opening up or backfilling of cable trenches when there is a risk of settlement
10、of work carried out by others. Trencl*. Sec Subclause 2.3 of Section DR. Laying of Pipes (Subclauses 5.2.2 and 5.3.1). Where a PVC pipeliue is jointed with positive solvent- welded jolnts, the effect oE the change in temperature during pipe laying may be reduced hy making the joints at ground level.
11、 lowering the pipeline into the trench, and then filling the pipeline with water. The fjlling with water has the further eEEect of providing some internal support to the walls of the pipe during hackfllling. After the pipe has been firmly and uniformly bedded, backfill should be placed in the trench
12、. up to the level of the top of the pipe, in layers of thickness not exceeding 150 mm. Each layer should be compacted to the specified density. Care should be taken to avoid a sideways shift of the pipe. During compaction the moisture content of the backfill should be within 2 X of OEIC. Where sheet
13、ing is used, the backfill should be placed as the sheeting is pulled (to prevent voids being left adjacent to the bedding). After the sLde fills have been compacted to the required density, a 300 mm thick layer of the same material should be placed over the top of the pipe and tamped lightly. Excess
14、ive tamping of this layer shon?d be avoided as it may result in distortion of the pipe. The trench should be kept clear of water until backfilling has been completed. The remainder of the hackfill should be placed and compacted in uniEorm layers so as to completely fill the trench, with no unfilled
15、spaces in the backfill. No rolling or heavy mechanical compaction should be done until at least h00 mm of material has been placed over the pipe. When pipes oE length oE the order of 6 m are laid, it may be found that, owing to storage in warm conditions without complete and level support, or for ot
16、her reasons, the pipes are slightly bowed. T.f a close conformity to line and gradient is required, it will be necessary to check and adjust the straightness and gradient of pipes at intervals more frequent than at pLpe ends only. Such pipes should be laid on the consolidated underbed with the how c
17、oncave upward and the how straightened by loading the two ends with hackfill (leaving a space at the joints for jointing and test observation) and carefully consolidating at the sides and over the pipe to bring the top of the pipe to true line and level (as checked by line and boning rod, or other m
18、eans of suitable accuracy), con- tinuing the process along the length of the pipe and checking Line and grade at suitahle intervals until the pipe is completely covered (except for the spaces at the joints) by properly consolidated backlil l. If the two ends of the pipeline are open and accessible a
19、nd thr pipeline is straight between them, a conflrmatory visual check may be made on the bore of the pipe by the use of a lamp and a mirror. Where pipes are to be laid in fill at, or above, natural ground level, the fill should be deposited and compacted to a height oE about 1 m above the proposed l
20、evel of the top of the pipe. Then a trench should be cut For the pipe in the fill and the pipe laid Ln the manner already described for laying below ground. SABS 0120 : Part 5 Section LC-1981 Cable ducts 3.2.3 Joltlting oE Pipes (Subclause 5.3.1). The following rules sllould be applied to tensrrre s
21、ound work.- manship: a) Jointing of pitch-impregnated fibre pipes 1) Pitch-impregnated fibre pipes, which have tapered ends, are jointed by means oE tapered socket couplings. Each pipe end and the inner surface of each coupling should be checked to ensure that they are clean before the spigot is pus
22、hed into the socket. 2) The end of the first pipe to be placed in a trench should he butted firmly against a solid object to ensure that hammer blows applied to subsequent pipe lengths will drive the pipe ends firmly into the sockets. A coupling shocld he fitted to the Leading end of the pipe and ta
23、pped firmly home by means of a 1,8 kg hammer applied to a wood block of size, say, 230 mm X 175 mm X 50 mm, held flush against the end of the coupling. The end of the next pipe length ulrould be inserted into tile coupling and a coupling placed over its leading end. This pipe length should then he t
24、apped home and the process repeated throughout the length of the line. In general, the pipe should not be driven further into the socket than 6 mm beyond hand tightness (see Drawing LC-5.1). 3) Any necessary cutting of pitch-impregnated fibre pipes should be done. according to the requirements of th
25、e works, by means of a sharp coarse-toothed saw. The cut ends of the pipes should be re-machined. Papering on site should be carrled out with a hand-turning machine recommended by the manufacturer of the pipes. h) Jointing oE steel or s un-iron i es I) EeeTor spun-iron pipzs of thoPsEigot and socket
26、 type should be jointed together by inr;rrrtlng the spigot or one pipe length into the socket of the end already in position. The spigot should be puslled. by means oE a crowbar, if necessary, as far as it can be made to move into the socket to erisure efficient caulking. Five turns of DRY spun yarn
27、 should then be wrapped around the spigot rind packed into the socket with a caulking tool. The yarn prevents the molten lead which is used to eal the joint from entering the pipe. 2) Lead should be melted in a metal pot and heated to a temperature of approximately 370 C. A plumbers ladle should the
28、n be used to pour the molten lead through the opening oC a “squirrel tail“ mould so that the annular space between the spigot and the socket is filled with lead. 3) When the lead has solidified, the mould should be removed and the lead tamped home with a hammer and caulking tool. While the ladle is
29、not in use, It should be inverted and placed over the me1 ting pot so that it is kept warm and dry. 4) Steel or spun-iron pipes with spigot ends only should be jointed by means of couplings. c) Bonding of steel or spun-iron pipe joints. An electrical hond should he provided across each joint between
30、 adjoining lengths oE steel or spun-iron. The bond should be in the form of a copper strip of dimanslons 13 mm X 3 mm X 250 mm, welded to the pipe end on each side of the joint as follows (NOTE: The copper strip will he supplied by the employer, if the employer is the GPO.): l) Clean an area oE the
31、pipe of size approximately 40 mm X 40 mm down to the hare metal by removing the coating of bltumen. 2) Place the copper strip in position on the cleaned surface and weld it to the pipe by means oE 3,3 mm approved welding rods for bronze and a d.c. welding unit set at 100 A. 3) Check every weld for s
32、oundness by applying tension by hand to the copper strip in a dire-tion away from the pipe while applying blows with a hammer of mass approximately 115 g to the side of the coppcr strip at the weld. d) llonding of steel or spun-iron pipes at manholes. The pipes: on each side OF a manlmle or draw pit
33、 should be bonded together by means oE a 13 mm X 3 mm copper strip (which nay be supplied by the employer) welded to each pipe by the method given in (c) above. The group of plpes on one side of the manhole should be bonded to the group of pipes on the other side by means of n 13 mm X 3 mm copper st
34、rip of suitable length whfch should be laid outside the manhole. When additional oies are laid. they should be bonded to the acllacent existinn pipes. . . . - -. . e) Jofnting of asbestos cement pip% 1) Asbestos cement pipes have machined ends which are jointed by means of i) rubber couplingswhich s
35、hould be used in normally firm soil conditions and where a small amount of moisture may I)e permitted to enter the pipeline; and ii) ashestos cement collars with rubber sealing rings, which should be used where unsuitable soil conditions are encountered and where a dry pipe is necessary, for example
36、 below railway tracks. 2) A coupling or collar should be pushed onto one end of each length oE asbestos cement pipe ready to receive the bare end of the next length as it is laid in the trench. Pipe ends should butt firmly against the ridge in the centre of the rubber coupling or the rubber ring in
37、the centre of the asbestos cement collar, as relevant. 3) Where a nest of pipes is Laid, joints should he staggered to increase the rigidity of the nest of pipes as a whole. E) Joint in of PVC i es. PVC pipes should be jointed together as follows: .igx ro6ughen thePiKside of the socket and the outsi
38、de of the pipe end with emery cloth. Apply PVC solvent cement to the inside oC the socket and the outside of the pipe end, Quickly insert the pipe end intn the socket. 4. QUALITY CONTROL AND OTHER CONSIDERATIONS 4.1 GENERAL. The relevant recommendations of SABS 0157) should be applied to the constru
39、ction of cable ducts. 4.2 DISPUTES. MEDIAPIONS, ARBITRATIONS, AND COURT CASES. Most disputes arise because of inadequately compacted backfill in trenches and divided responsibility for construction work carried out in the trench and over the top of the bedding. 1) Quality management systems. I l“ Drawing LC-5.1- Jointing Pitch - Impregnated Fibre Pipes
