Issues with material loss during instrument installation
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I would like to ask the experts: what is the normal loss rate for pipes and profiles used in instrument installation in engineering projects? Or, after the design institute specifies the quantity required for construction, what additional amount is acceptable according to the construction team’s requirements? Are there any relevant standards for this? Or strict control systems?
The quantity provided by the design institute already takes factors such as losses into account; no additional amount is needed, unless the design itself is of poor quality. What I do is add up the values in the material database and then multiply them by the corresponding coefficients as specified.
The construction party procures materials in accordance with the material list specified in the design; if there is a shortage, a design change order can be issued by the designer to make up for it.
Which standard is being referenced?
HGT 20637.7-1998 Statistics on Materials for Instrument Installation
The design institute has taken losses into account when preparing the material list; the quantities proposed by the construction team must not, in principle, exceed those specified in the design. If it exceeds the designed amount, the construction team must identify the specific aspects that are missing or omitted from the design, and the designer must then issue a new design change. The owner also needs to verify the construction materials against the construction drawings in order to review the contractor’s submitted information.
A margin is generally taken into account during design; the quantities are usually based on the drawings, and even if they are estimated, there is a basis for such estimates, so the differences are not significant； If there is a significant discrepancy between the actual amount installed and the amount specified in the design, it is usually caused by one of the following factors: omissions during the design phase (this occurs very rarely), misappropriation of materials during construction, failure to follow the design drawings, or changes to the route or installation method.