• 14 taboos of installing a valve (Part Four)

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14 taboos of installing a valve (Part Four)

  • 08 21, 2018

Taboo 12

The specifications and models of the installed valves do not meet the design requirements.

For example, the nominal pressure of the valve is less than the system test pressure. The water supply branch pipe adopts a gate valve when the pipe diameter is less than or equal to 50 mm. The dry pipe and the stand pipe of the hot water heating adopt a globe valve, while the suction pipe of fire pump adopts a butterfly valve.

Consequences: Affect the normal opening and closing of the valve and its function like regulating the resistance and pressure. Even when the system is running, the valve is damaged and needs to be repaired.

Measures: Be familiar with the application range of various types of valves, and select the specifications and models of the valves according to the design requirements. The nominal pressure of the valve must meet the requirements of the system's test pressure. According to the requirements of construction specifications, when the diameter of the water supply pipe is less than or equal to 50mm, a globe valve should be used, and when the pipe diameter is more than 50mm, the gate valve should be used. The hot water heating control valve shall be a gate valve, and the suction pipe of fire pump shall not adopt the butterfly valve.

Taboo 13

Do not perform the necessary quality inspection before installation of the valve.

Consequences: The valve switch does not work well during the operation of the system. If the switch isn't turn off to the right place, the water(steam) leakage occurs, causing the necessity of reworking and repairing, and even affecting the normal water (steam) supply.

Measures: Before the valve is installed, the compression strength and tightness test should be done. The spot check shall be carried out on 10% of each batch (same grade, same specification, same model) and not less than one.

For closed-circuit valves installed on the main pipe, the compression strength and tightness test shall be made one by one. The strength and tightness test of the valve shall be in accordance with the Standards of Acceptance of Construction Quality of Building Water Supply and Drainage and Heating Engineering (GB 50242-2002).

Taboo 14

The main materials, equipment and products used in construction lack technical quality appraisal documents or product certificates that meet the current national or ministerial standards.

Consequences: The quality of the project is not up to standard and there are hidden dangers. The project cannot be delivered on time and must be reworked and repaired, resulting in construction delay and increased investment in labor and materials.

Measures: The main materials, equipment and products used in water supply, drainage, heating and sanitation projects shall have technical quality appraisal documents or product certifications in accordance with the current standards issued by the State or the Ministry. Their product names, models, specifications and national quality standard codes shall be indicated as well as date of production, manufacturer's name and location, factory product inspection certificate or code.

 
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