Valves are devices used in fluid systems to control the direction, pressure, and flow rate of fluids. They are devices that enable the flow or cessation of media (liquids, gases, powders) in piping and equipment, and can control their flow rate. During the construction process, the installation method of valves will directly affect their normal operation in the future. Today, the editor will summarize some precautions for valve installation.

Taboo 1: The main materials, equipment, and products used in construction lack technical quality appraisal documents or product qualification certificates that comply with current national or ministerial standards.

Consequence: The engineering quality is unqualified, there are hidden dangers of accidents, and it cannot be delivered for use on schedule. It must be reworked and repaired; Causing delays in the project schedule and increased investment in labor and materials.

Measures: The main materials, equipment, and products used in water supply and drainage and heating and sanitation projects should have technical quality appraisal documents or product qualification certificates that comply with the current standards issued by the state or department; It should indicate the product name, model, specifications, national quality standard code, date of manufacture, manufacturer name and location, and factory product inspection certificate or code.

Taboo 2: Failure to conduct necessary quality inspections before valve installation according to regulations.

Consequence: During system operation, valve switches are not flexible, valves are not tightly closed, and water (steam) leakage occurs, resulting in rework and repair, and even affecting normal water (steam) supply.

Measure: Before installing the valve, a pressure strength and tightness test should be conducted. The experiment should randomly select 10% of each batch (of the same brand, specification, and model), and not less than one. For the closed-circuit valves installed on the main pipeline for cutting off, strength and tightness tests should be conducted one by one. The strength and tightness test pressure of valves shall comply with the provisions of the "Code for Acceptance of Construction Quality of Building Water Supply, Drainage and Heating Engineering" (GB 50242-2002).

Taboo 3: 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; When the diameter of the water supply branch pipe is less than or equal to 50mm, a gate valve shall be used; The dry and vertical pipes for hot water heating use shut-off valves; The suction pipe of the fire pump adopts butterfly valve.

Consequence: Affects the normal opening and closing of valves, as well as the adjustment of resistance, pressure, and other functions. Even causing valve damage during system operation and forcing repairs.

Measure: Familiarize yourself with the application scope of various valves and select the specifications and models of valves according to the design requirements. The nominal pressure of the valve should meet the requirements of the system test pressure. According to the construction specifications, if the diameter of the water supply branch pipe is less than or equal to 50mm, a shut-off valve should be used; When the diameter of the pipe is greater than 50mm, a gate valve should be used. The dry and vertical control valves for hot water heating should use gate valves, and the suction pipes for fire pumps should not use butterfly valves.