7.3　Piping Installation

7.3.1　The machining，welding，installation，purging and cleaning and quality inspection during the pipe construction shall comply with the requirements in the design document and current national standards GB 50235 Code for Construction and Acceptance of Industrial Metallic Piping，GB 50236 Code for Construction of Field Equipment，Industrial Pipe Welding Engineering and GB 50683 Code for Acceptance of Field Equipment，Industrial Pipe Welding Construction Quality.Sealing gaskets shall，according to the fluid characteristic of the pipe，be fitted on all spots where the flange connection or holt-down connection is adopted.

Check method:Checking the design documents and quality inspection records made during the construction，on-site sampling inspection.

Sample size:10%，doubling the sample size upon any nonconformity.

7.3.2　Installation of the pipe valves shall comply with not only the requirements in design documents and instructions but also those in current national standard GB 50235 Code for Construction and Acceptance of Industrial Metallic Piping.

Check method:Checking the construction records，on-site inspection.

Sample size:10% and at least 1 piece，double sample size upon nonconformance.

7.3.3　The bursting disk shall be fitted in each air branch pipe in the furnace area of the gas-burning reheating furnace.Such disk should be on the end of the pipe，its outlet shall be away from the walkway and with protection net，and its selection and use shall comply with the requirements in the design document.

Check method:Checking the technical design documents，field inspection of the installation.

Sample size:100%.

7.3.4　Attention shall be paid to the problem of dew condensation of low temperature flue gas in the flue duct of the combustion system.Drainage device shall be installed at the lowest point of the flue duct and the low point of the flue duct before the suction fan.

Check method:Field inspection.

Sample size:100%.

7.3.5　Corrosion protection and painting of the piping shall not only comply with the requirements in the design document but also those in current professional standard HGJ 229 Code for Construction and Acceptance of Industrial Equipment and Piping Anticorrosion Works as well as the following requirements:

1　Rustproof measures such as painting shall be taken on the external surface of the overhead pipe.Before being painted，the pipe surface shall be cleared of any rust，welding slag，burr，oil，water and other dirt.

2　Paint thickness of piping shall meet the requirements in the design documents.

3　The selected paint shall be capable of resisting the corrosion by the ambient air，shall meet the highest working temperature requirement of the fluid transmitted by the pipe and be provided with relevant certification.

4　The under coat shall match with the top coat for the pipe painting.But the pipe with external heat insulation layer may be coated with the under coat only.

5　The outer surface of piping of stainless steel，nonferrous metal，galvanized steel and the like should not be painted.

6　The color and logo of piping shall comply with the requirements in current national standard GB 7231 Basic Identification Colors and Code Identification and Safety Sign for Industrial Pipelines.

Check method:Checking the material quality certificate，construction records and other the documents of corrosion protection and painting，field inspection of the appearance quality and color.

Sample size:100%.

7.3.6　Heat insulation of the hot blast piping shall comply with the requirements in the design document and current national standard GB 50264 Design Code for Insulation Engineering of Industrial Equipment and Pipe，construction process and quality control shall comply with the requirements in current national standard GB 50126 Code for Construction of Industrial Equipment and Pipeline Insulation Engineering.

1　Installation of heat insulation of the pipe shall be conducted after the pipe painting is accepted.The outer surface of the pipe shall be kept clean and dry before the installation of heat insulation，and measures of preventing frost，rain and snow shall be taken in the construction during the winter or rainy season.

2　The heat insulation material for the pipe shall have the quality certificate or analysis and test documents offered by the manufacturer，moreover，the type，specification and performance of the material shall meet the requirements in the design documents.

3　Installation of heat insulation of the pipe shall be executed orderly on the pipe one by one，except for the heat tracing pipe.

4　Quality acceptance of bricking layer of the pipe with internal heat insulation shall comply with the requirements in Chapter 6 of this Code.

5　Installation of heat insulation on the pipe which needs to be purged with steam should be conducted after the purging.

Check method:Checking the design documents and construction records，on-site visual inspection and thickness sampling inspection.

Sample size:100%.

7.3.7　The deviation of the concentricity between motor shaft and main shaft coupling shall be checked during the installation of fans.Such deviation shall comply with the requirements in current national standard GB 50231 General Code for Construction and Acceptance of Mechanical Equipment Installation Engineering.

Check method:Measuring with dial indicator.

Sample size:100%.