SANS 10120-3 LD-1982 Code of practice for use with standardized specifications for civil engineering construction and contract documents Part 3 Guidance for design Section LD Sewer.pdf

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 3 Section LD-1962 Sewers PART 3 : GUIDANCE PUR UESlGll CONTENTS Clause .- 1 . 1.1 1.1.1 1.1.2 1.1.3 1 . 1.4 1.3.5 1.1.6 1.2 1.2.1 1.2.2

4、1.3 1.3.1 1.3.2 1.3.3 1.3.4 1.3.5 1.3.6 1.3.7 l 3.8 1.3.9 1.3.10 1.3.11 1.3.12 1.3.13 1.3.14 L. 2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6 2.1.7 2.1.8 2.1.9 2.1 10 2.1.11 2.1.12 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.8 2.2.9 2.3 2.3.1 2.4 3 . 3.1 4 . 4.1 4.2 4.2.1 4.2.2 4.2.3 4.3 4.4 4.4.1.

5、4.4.2 4.4.3 4.4.4 4.4.5 5 . lage Number PRIS-TIINUER CONSIDERATIONS 1 lrtvcstigations + 1 High strength vitrified clay pipes 1 Joints for vitrified clay pipes 1 Sand for plaster and mortar 1 Step irons . 1 Connecting sewers with depth of drop greater than 3 In l Mnintenance methods 1 Adrninfstration

6、 . 1 Alterlrative materials l Pitch-impregnated fibre pipes 1 Document.ation 1 . Chemical effluents 1 Pitch-impregnated fihre pipes . 1 Joints . 1 Bricks for manholes. etc . 1 Step irons . 1 Materials and methods of construction for manholes and chambers 1 Drop connectiors . l Protection of shallow

7、pipes 1 . Tolerances and variation of permissihlc deviations 2 Testing 2 Details in schedule for connection to existing sewer . 2 Scheduling large manholes . 2 other documentation requirements . 2 Risinq nrains 2 DESIGN REQUIREMENTS 2 Design Criteria 2 General . 2 Drsi.gn of bedding for pipes 2 Deta

8、il on drawings . 2 Intersecting services 2 Hydraulic design . 2 Maximum gradients and anchor blocks . 2 Mi.nimum gradients 2 Location of manholes 3 Connr?c;tions to drainage systems 3 Depth of drop at crrnnoctions . 3 klinirnum cover over sewers 3 Curvcs in pipelines of vitrified pipes 3 Natpriais 3

9、 Flexible pipes . 3 Couplirigs for vitrified clay pipes 3 Joints in vitrified clay pipes 3 Class of AC pipes and type of joints . 3 Straightness of AC pipes . 3 Pitch-impregnated fibre pipes Ashpstos cement manholes . Effect of sulphates ines are used it would be ilXogical to decline the use of AC m

10、anholt?. . - 2.2.0 et. c ulhate on p and Manhole. Consider the followinr before scheduling or spc,:ifyitig articular materials for pipelines and manholes: a) The disintegration of pipes carrying sewage is caused mainly by condensation on the roof of the pipes. Manholes and chambers, being more open,

11、 are less vulnerable to this type of disintegration; b) marholes and chambers are more accessible than pipelines for inspection and repair; c) the stresses in the walls of manholes are lower than those in pipe walls. 2.9 Infiltration at Manholes (See also Subclause 3.1.8 of Section LD of Part 5 of t

12、he code). Infi.ltration j.nto sewers is a common problem that is costly in the long term because it increases the volume of liquid for which provision must. be made in the design of sewage treatment works. Leakage into manholes is a significant source of infiltration and, generally speaking, the cos

13、t of making manholes watertight to minimize infiltration from this source is negligible when compared with the cost, of ignoring this source of infiltration. Therefore, design and specify in such a way as to minimize infiltration. One source of infiltration is seepage through the floor or base of th

14、e manhole. SABS l200 LB“ specifies, for most pipelines, that the pipes leading to a manhole be laid in a granular bed. This bed acts as an ideal watercourse for underground water that, on reaching the manhole, is blocked by the concrete base. Infiltration is almost inevitable if the base has been po

15、orly constructed or if cxternal ground water pressures are high because the manhole is deep and/or the water table is high. Consider improving the watertightness of manholes by requiring that care be exercised and that steps such as the following be taken: a) Use the method shown in Drawing LD-3.1 t

16、o deal with the problem of infiltration at the base of the manhole and at the joints between pipeline and manhole. b) Recluce infiltration through walls l) in the case of brick manholes, by plastering the walls outside or i.nside (or both); 2) in the case of precast corrcrete manholes (Subclause 3.5

17、.2 of SABS 1200 LD), by sealing the joints between successive precast rings by means of a polyurethane cement or a bitumastic filler that is applied to the top of each ring onto which another is to be placed, the joint being trowelled smooth and the adjacent surfaces primed and covered with self-adh

18、esive tape. 2.3 ANCILLARIES 2.3.1 Concrete Casing to PJ b) arter the initial hackfilling has been conpleted. Standard equipment is available Tor conducting air tests. This equipment includes a comprc!ssor driven by a petrol engine and is portable. The pxessure is indicatecl on both a dial gauge and

19、a water manometer. 2) See p. I. 6) Pitch-imprrpatr.rl fibre pipes and couplings. 7) The installation of polyrthylene and unplasticieed polyvinyl chloride pipes. 8) Structural design and installation of precast concrete pipelines. 9) Installation of spweraye and drainage non-pressure pipelines. SABS

20、0120 : Part 3 Section LD-l982 Sewers 4.2.2 Method. Carry out tha air test under stable tcmpsrature conditions as the method is sensitive to temperature variations. Use the followinq test method: a) Saturate the pipelino with water hecore tes51ig. b) Attach the appropriate size sewer test plug to the

21、 air hose and insert the hose into one end of the pipeline to be tested. Plug off the otner end and all other openings, c) Adjust the water level in the manomotet to zero on the scale. dj Pressurize the pipeline and mantain a pressure of 3,75 RPa as indicated on thc dial gauge (375 mm on the manomet

22、er). Hold the prcssure at this level for a period of 2 min to allow the temperature to stabilize. During this time test the plugs hy means of soapy water for air leaks. n) At: the end of the 2 rnin period adjust the pressure to slightly in excess of 250 mm on the manometer /2,5 kPa), then close the

23、shut-off valve and switch off the compressor engine. L) When the manometer reading Calls to 250 mm, staxt a stop-watch and record the time taken for the manrimetor reading to drop from 250 nun to ?25 mm. g) Compare the recorded tjmc with the minimum time specified for the particular pipe diameter in

24、 SubcXause 7.2.1 of SAX4 I200 LD. 4.2.3 gocedure in the Event of Failure. Should a section of pipeline fail the air test, carry out an invcstiqation as follows: a) Check that all, stoppers to erf connections are sealed; b) check that manhole connections are sound: C) carry out further air tests usin

25、g isolator bays to locate the fault; d) if no success is achieved with (a), (b), or (c) above, carry out a water test on the line. 4.3 WATGR TEN (Subclause 7.2.2). Use the followincj procedure: a) Block the lower end of the pipeline with suitably braced plugs. b) Check that all connectiorie and bend

26、s are tjyht and stable. c) F311 the pipeline until a head of 1,2 m of water is achieved at the head of the line. (NOTE: The pressure at the lower end should not exceed that equivalent to a head of 6 m of water.) d) Allow the system to stabilize for at least 10 min, i.e. allow water to be absorbed by

27、 the pipeline and ajr to escape at the joints. e) Measure the loss of water over a 30 min period by adding water from a measuring vessel every 10 min in order to maintain the head at 1,2 m. f) Check that the leakage rate does nut exceed the applicable value specified in Subclause 7.2.2 of SABS 1200

28、LD. 4.4 TESTS ON FLEXIi3LE JOINTS (Subclause 3.1.7 and see also DS 65“) and ASTM C 45) NOTE: Some joints (such as sleeve assemblies) are designed to accommodate line displacement, and others to resist shear loading. 4.4.1 lacement Test. Subject a joint assembly that will allow dispiacement, to a rel

29、ative displacement between adjacent pipes of 0,04 mm/mm of pipe diameter in a plane normal to the axes of the pipes and, while holding the pipes in this state, subject them to an internal watcr pressure of 60 kPa (6 m of water) for 5 min. There shall be no visible leakage at the joint. 4.4.2 Shear t

30、oading Test. Subjcct a joint assembly that will not allow line displacement, to a water pressure of 60 kPa for 15 min while applyiny a shcar load of 25 N per millimetre of pipe diameter uniformly behind the socket. There shall be no visible leakaqe at the joint. 4.4.3 t1astomeric Materid used in Mak

31、ing Joints. Where elafitcneric material such as polyurethane is used in making the joints in a vitrified clay pipeline, specify that the contractor is to have the material tested by the manufacturer to prove compliance with ASTM C 42“. 4.4.4 Eeijection Tcs. Subject the flexible joint to an internal

32、water pressure of 60 kPa for 5 min with the pipes or fittings deflected a5 follows and check for compliance with Subclause 3.1.7 of SABS 1200 LDr a) Vitrified clay pipes llominal bore, / Deflection b) AC and concrete pi=. Use deflections given by the manufacturer. 4.4.5 Draw Test. Subject pipe joint

33、s to an internal watcr pressure of 60 kPa for 5 min while the pipe or fitting ends are separated by 10 mm and check for compliance with Subclause 3.1.7 of SABS 1200 LD. 5. QUAISTY CONTROL AND OTHER CONSIDERATIONS 5.1 Apply the relevant recommendations of SADs 015712) to the design of sewers. 10) Vit

34、rified clay pipes, fittings and joints. 1L) Compression joints for vitrified clay pipes ad fittings. 12) Quality management systems. SABS 0128 : Part 3 Section LD-1982 Sewers FLEXIBLY JOINTED PlPE AS PER DWG. L0 -2 IN SABS 1200 LD FLEXIBLY JOINTED PIPE AS PER DWG. LD-2 IN SABS 1200 LD I - Permanent

35、Tr DROP NOT TO EXCEED 1200mm DROP SABS 0120 : Part 3 Section LD-1982 Sewers PRECAST MANHOLE PRESCRIBED MIX 20 CONCRETE a) For Drops up to 1,2m PRECAST MANHOLE PRESCRIBED MIX 20 CONCRETE b) For Drops Exceeding 1,2 m NOT E : FLEXIBLE CONNECTIONS AS PER DWG LD - 2 IN SABS 1200 LD Drawing LD -3.2- Conve

36、ntional Drop Connections SABS 0120 : Part 3 Section 1.D- 3.982 Sewers PIPE ON FIRM GRANULAR SABS 0120 : Part 3 Section LD- l982 Sewers PRECAST MANHOLE PRECAST MANHOLE a) Sewer Connections for Drops of 1,2 to 3,O m r PRECAST SECTIONS b) Vortex Connections for Drops greater than 3,Om NOTE : FLEXIBLE J

37、OINTS AS PER OWG LD-2 IN SABS 1200 LD Drawing LD -3.4 - Other Drop Connections SABS 0120 : Part 3 Section .LD- 1 982 Sewers COMPACTED SELECTED FILL BLANKET- GRANULAR BEDDING CRADLE - a) GENERAL CASE CAST-IN- SlTU CONCRETE SLAB AT SURFACE 7 COMPACTED S ELECTED FILL BLANKET - P) 3QOrnm IN GRANULAR SEWVITUDES BEDDING CRADLE (bE GQOrnrn IN ROAD RESERVES b) LIMITING CASE NQIE: (1) DETAILS AND THICKNESS OF CONCRETE SLAB AS ORDERED TO SUIT LOADS AND TRENCH WIDTH. CLAUSES 2.1.10 AND 2.3.1. lSBW 0-626-86327-2 sabs pta