CJJ/T 254-2016 in English

CJJ/T 254-2016 Technical specification for leakage surveillance system of directly buried heating pipe

1 General provisions

1.0.1 This specification is developed in order to improve the safety and reliability of directly buried hot-water network for urban heating, standardize the design, construction, debugging, acceptance, operation and maintenance of the leakage surveillance system of directly buried hot-water insulation pipelines for urban heating.

1.0.2 This specification applies to the design, construction, debugging, acceptance, operation and maintenance of leakage surveillance system for prefabricated directly buried hot-water pipeline made of polyurethane foam with high-density polyethylene outer casing.

1.0.3 The leakage surveillance system shall be designed, constructed and accepted synchronously with the surveilled pipe network.

1.0.4 The design, construction, debugging, acceptance, operation and maintenance of the leakage surveillance system for directly buried hot-water pipelines shall comply with the current national standards in addition to this specification.

 
2 Terms

2.0.1 leakage surveillance system
system for surveilling and locating the leakage of directly buried hot-water pipeline

2.0.2 surveillance circuit
uninterrupted measuring circuit consisting of directly buried hot-water pipes and fittings with signal wires, and measuring points

2.0.3 measuring instrument
electronic instrument used in a surveillance circuit to detect and locate disorder points and moisture points and to transmit signals

2.0.4 host computer system
software system and hardware device used for transmitting, storing and displaying the on-site testing data and leakage information of the leakage surveillance system

2.0.5 disorder point
point where the open circuit occurs to signal wire in the surveillance circuit or short circuit occurs between the signal wire and the steel pip or between signal wires

2.0.6 moisture point
point where the thermal insulation between the signal wire and the steel pipe is affected by moisture

2.0.7 signal wire
metal wire buried in the thermal insulation of prefabricated directly buried insulation pipe and fitting, intended for the detection of disorder point, moisture point and the transmission of electronic signals

2.0.8 measuring point
point where the surveillance circuit is opened and the measuring instrument is connected to the surveillance circuit during detection and fault positioning

2.0.9 starting point
starting point of the surveillance circuit

2.0.10 ending point
ending point of the surveillance circuit.

2.0.11 connecting point
connecting point that spans a device and a pipe fitting without conditions for prefabricated thermal insulation in the surveillance circuit

2.0.12 connecting cable
cable used at the spanning of measuring point and connecting point in the surveillance circuit

2.0.13 fixed surveillance device
device fixed in a room for automatic collection, recording and remote transmission of alarm information for directly buried hot-water pipeline

2.0.14 portable test device
portable device intended for on-site testing, positioning of moisture points and disorder points

 
3 Design

3.1 General requirements

3.1.1 The leakage surveillance system should adopt resistive-type leakage surveillance system or impedance-type leakage surveillance system.

3.1.2 The leakage surveillance system shall be designed according to the overall layout of the heating network, and there shall be room for expansion.

3.1.3 The leakage surveillance system shall be designed according to the design drawings of the heating network and the technical requirements of the leakage surveillance system.

3.1.4 The design documents of the leakage surveillance system shall include design description, material list and design drawings, and shall comply with the following requirements:

1 The design description shall specify the design and construction requirements, acceptance criteria and precautions for use and maintenance of the leakage surveillance system;

2 The material list shall contain information such as the description, model and quantity of the materials used in the leakage surveillance system;

3 The design drawings shall indicate the installation locations of the accessories of the leakage surveillance system.

3.1.5 When the design of heating network is changed, the design of the leakage surveillance system shall also be changed.

3.1.6 Prefabricated directly buried hot-water insulation pipes and fittings with signal wires shall be adopted in the heating network with leakage surveillance system.

3.1.7 The leakage surveillance system shall be divided into surveillance circuits according to the design drawings of the heating network, and the surveillance circuits shall meet the following requirements:

1 Each surveillance circuit shall include one starting point, one or several measuring points and connecting points, and one ending point;

Foreword iii
1 General provisions
2 Terms
3 Design
3.1 General requirements
3.2 Composition of leakage surveillance system
3.3 On-site test unit and central surveillance unit
4 Materials and apparatus
4.1 General requirements
4.2 Materials
4.3 Apparatus
5 Construction
5.1 General requirements
5.2 Construction of signal wires
5.3 Installation of instruments and accessories
5.4 On-site testing and repair
6 Debugging and acceptance
6.1 General requirements
6.2 Debugging
6.3 Acceptance
7 Operation and maintenance
7.1 Operation
7.2 Maintenance
Annex A Testing records of leakage surveillance system
Annex B Acceptance reports of leakage surveillance system
Explanation of wording in this specification
List of quoted standards
Explanation of provisions