GB/T 12772-2026Cast iron pipes, fittings and accessories with flexible joint for building drainage (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document supersedes GB/T 12772-2016 "Flexible Joint Cast Iron Pipes, Fittings and Accessories for Drainage" and is consistent with GB/T 12772-2016.

Compared to previous versions, aside from structural adjustments and editorial changes, the main technical changes are as follows.

a) The scope has been changed (see Chapter 1, Chapter 1 of the 2016 edition);

b) Terms and definitions have been changed (see Chapter 3, Chapter 3 of the 2016 edition);

c) The wall thickness dimensions and unit weight of type W, W1, and B pipe fittings have been changed (see 5.1.1, 5.2.1, and Appendix A, 2016 edition).

5.1.1, 5.2.1 and Appendix A);

d) Combine type B1 and type B2 pipe fittings into type B pipe fittings (see Table 3, Figures A.88 to A.122 and Tables A.88 to A.122, 2016).

(See Figures 7, Table 6, Figures A.89 to A.121, and Tables A.89 to A.121 of the version).

e) Added the clause "Type B fittings should be used in conjunction with Type W straight pipes" (see 5.2.2.4);

f) Large-radius elbows for Type A, Type W, and Type B pipe fittings have been added (see Figure A.2, Table A.2, Figure A.36, Table A.36, Figure A.89, and...).

Table A.89);

g) A hemispherical vent cap was added (see 5.2.2.6, Figure A.77 and Table A.77);

h) The structural dimensions of the H-tube were modified, and anti-backflow structural requirements and marking requirements were added for the height difference between the two ends of the venting inclined tube (see 5.4.3).

9.2, Figures A.17, A.37, A.72 and A.104, 5.4.3, 9.2, Figures A.17 and A.37 in the 2016 edition.

Figures A.72 and A.104);

i) The dimensions of the water-replenishing trap structure have been changed, and a requirement has been added that the height difference between the water inlet and outlet is greater than or equal to 10mm.

(See Figure A.6, Table A.6, Figure A.32, Table A.32, Figure A.69, Table A.69, Figure A.108, Table A.108, 2016 edition)

Figure A.6, Table A.6, Figure A.32, Table A.32, Figure A.69, Table A.69, Figure A.108, Table A.108);

j) The dimensions and markings of the riser inspection port and inspection port cover have been changed (see Figure A.19, Table A.19, Figure A.43, Table A.43, Figure A.76).

Table A.76, Figure A.92, Table A.92, Figure B.3, Table B.3, Figure A.19, Table A.19, Figure A.43, Table A.43 (2016 edition)

Figure A.76, Table A.76, Figure A.92, Table A.92, Figure B.3, Table B.3);

k) The excessively long interface dimensions of the Type A H-tube, Y-vent tube, and H-vent tube were changed (see Figure A.16, Table A.16, Figure A.17).

Table A.17, Figure A.18, Table A.18, Figure A.16, Table A.16, Figure A.17, Table A.17, Figure A.18 (2016 edition)

Table A.18);

l) Infrequently used in-floor drainage fittings have been removed; the remaining in-floor drainage fittings are now classified as W1 type pipes, based on their connection to the toilet outlet.

Scope of application (see Appendix A, Appendix A of the 2016 edition);

m) Requirements have been added regarding performance dimensions, water seal depth, H-pipe venting angle tube height difference, inspection port opening diameter, and cleanout port opening diameter.

(See 5.4);

n) Change "free length" to "interface sealing area length" (see 5.4.1, Figure 9 and Table 6; 5.2.3, Figure 9 and Table 7 in the 2016 version);

o) Change "Dimensional tolerances" from "Dimensions" to "Structural Dimensional Tolerances" (see 5.5, 7.6.4, and 5.4 and 7.6 in the 2016 version);

p) Added requirements for the inner and outer diameter deviations of the same pipe ends, and straight pipes and fittings of the same series (see 5.5.1.3, 5.5.1.4);

q) The permissible lower deviation in weight for straight pipes and fittings has been modified, narrowing the range of permissible lower deviation (see 5.6.2, 5.6.3, 2016 version).

5.6.2, 5.6.3);

r) The phosphorus content requirements for cast iron have been changed (see 6.1, 2016 edition of 6.1);

s) The tensile strength was changed to the bulk tensile strength, and the specimen dimension diagram and test method were added (see 6.2.1, 7.2.1, 2016 version).

6.2.1, 7.2.1);

t) The external water pressure test has been changed to a negative pressure resistance test (see 6.3.2, F.7, 2016 version of 6.3.2, F.7);

u) Added requirements and testing methods for riser drainage capacity (see 6.3.5, 7.3.4).

v) Added drainage noise requirements and test methods for straight pipes and fittings used in building drainage piping systems (see 6.3.6, 7.3.5);

w) It adds a provision prohibiting the use of putty to conceal casting defects such as porosity, sand holes, honeycomb, and substandard wall thickness in straight pipes and fittings.

Requirements (see 6.4.1);

x) An additional requirement has been added that pipe fittings with complex internal structures should be formed using resin sand core casting (see 6.4.4);

y) A new requirement has been added prohibiting the use of water-based putty as a base coat for anti-corrosion coatings (see 6.5.1);

z) Added specifications for the coating thickness on the inner and outer surfaces of straight pipes and fittings (see 6.5.2);

aa) The requirement for W1 type straight pipes and fittings to use epoxy resin anti-corrosion coating has been added (see 6.5.3);

(bb) Four coating properties have been added to the inner surface of W1 type straight pipes and fittings. adhesion, salt spray resistance, acid and alkali resistance, and temperature change resistance.

Performance requirements and test methods (see 6.5.5, 7.5.5);

(cc) Two coating performance requirements have been added for the inner surface coating of Type A and Type W straight pipes and fittings, and Type B fittings. adhesion and salt spray resistance.

and detection methods (see 6.5.6, 7.5.7);

(dd) Added adhesion requirements and test methods for the outer surface coatings of straight pipes and fittings, as well as for coatings used outdoors on the outer surface of straight pipes and fittings.

(See 6.5.7 and 7.5.4);

(ee) Added a test method for the weight of straight pipes and fittings (see 7.6.5);

(ff) The type testing regulations have been revised, simplifying the periodic retesting procedures determined by the type of straight pipe and fitting interface, the structural dimensions of the fittings, and the materials.

The re-inspection items (see 8.4) and other type inspection items are changed to once every three years (see 8.4.1);

(hh) An additional recommendation has been added that straight pipes should be packaged using wooden pipe supports, and pipe fittings should be packaged using slatted frames or jumbo bags (see 10.1);

i) A protective requirement has been added that "straight pipes and fittings stored in outdoor open-air areas should be covered with rainproof tarpaulins" (see 10.3);

j) The dimensions of the inspection port gland have been changed (see Table B.3, 2016 edition of B.3).

(kk) Added reinforced stainless steel clamps and anti-detachment clips for Type A and Type B interfaces (see 5.1.1.1, 5.1.1.2, Appendix C, 2016 edition).

5.1.1.1, 5.1.1.2, Appendix C);

l) Added reinforced stainless steel clamp rubber sealing sleeve, type A and type B shock-absorbing rubber sealing rings, and type C socket-type rubber sealing ring.

The sealing rings and the self-aligning disc sealing gaskets for the pre-embedded connecting pipes (see 5.1.1.1, 5.1.1.2, 5.1.1.4, Appendix D, 2016 edition) 5.1.1.1, 5.1.1.2, 5.1.1.4, Appendix D);

The requirement that "when using EPDM rubber, the EPDM rubber content should not be less than 25%" has been added, along with corresponding testing requirements.

Test methods (see D.3.1, D.4.1);

nn) A normative appendix, "Embedded Sleeves and Embedded Connectors in Floor Slabs," has been added (see Appendix E).

A normative appendix, "On-site Inspection and Acceptance", has been added (see Appendix I).

This document was proposed by the China Iron and Steel Association.

This document is under the jurisdiction of the National Steel Standardization Technical Committee (SAC/TC183).

1 Scope

This document specifies the classification, dimensions, and shapes of flexible joint cast iron straight pipes (hereinafter referred to as cast iron drainage pipes), fittings, and accessories for building drainage.

Condition, weight and permissible deviations, technical requirements, test methods, inspection rules, marking, quality certificate, packaging, transportation and storage.

This document applies to the ventilation of gravity-flow domestic wastewater, sewage, rainwater, and drainage systems in buildings, with a nominal diameter range of [missing information].

Flexible joint cast iron drainage pipes, fittings and accessories with diameters from DN50 to DN300 are used as a reference for drainage pipes of other industrial wastewater.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 223.59 Determination of phosphorus content in iron and steel and their alloys - Bismuth-phosphomolybdenum blue spectrophotometric method and antimony-phosphomolybdenum blue spectrophotometric method GB/T 223.68 Chemical Analysis Methods for Iron and Steel Alloys - Determination of Sulfur Content by Potassium Iodate Titration after Combustion in Tubular Furnace GB/T 223.72 Determination of sulfur content in iron and steel and their alloys by gravimetric method GB/T 228.1 Metallic materials – Tensile testing – Part 1: Test method at room temperature GB/T 231.1 Metallic materials – Brinell hardness test – Part 1: Test method GB/T 528 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber GB/T 1690 Test methods for resistance to liquids in vulcanized or thermoplastic rubbers GB/T 3098.1 Mechanical properties of fasteners - bolts, screws and studs GB/T 3098.6 Mechanical properties of fasteners - Stainless steel bolts, screws and studs GB/T 3512 Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air GB/T 7759.1 Determination of compression set of vulcanized or thermoplastic rubber – Part 1: Under normal and high temperature conditions GB/T 7759.2 Determination of compression set of vulcanized or thermoplastic rubber – Part 2: Under low temperature conditions GB/T 7762 Static tensile test for ozone cracking resistance of vulcanized rubber or thermoplastic rubber GB/T 9286-2021 Paints and varnishes - Cross-cut test GB/T 9439-2023 Gray Cast Iron Parts GB/T 9799-2024 Metallic and Other Inorganic Coatings - Treated Zinc Electroplating on Steel GB/T 10125 Corrosion test under artificial atmosphere - Salt spray test GB/T 13452.2-2008 Determination of film thickness of paints and varnishes GB/T 14837.1 Rubber and rubber products - Determination of composition of vulcanized and unvulcanized rubber by thermogravimetric analysis - Part 1: Butadiene Rubber, ethylene-propylene binary and terpolymers, isobutylene-isoprene rubber, isoprene rubber, styrene-butadiene rubber GB/T 20878 Stainless Steel Grades and Chemical Composition GB/T 24234 Determination of Multi-Element Content in Cast Iron by Spark Discharge Atomic Emission Spectrometry (Conventional Method) GB/T 30648.1 Determination of resistance to liquids of paints and varnishes – Part 1: Immersion in liquids other than water GB/T 30789.2-2014 Evaluation of aging of paint and varnish coatings. number and size of defects and degree of uniformity of appearance change.

Part 2: Evaluation of Foaming Grade