by Reservation and embedment is the most critical work in the early stage of mechanical and electrical installation project.
If the construction quality is not good, the post treatment often involves civil engineering, decoration and other disciplines, causing great trouble.
Therefore, special attention should be paid to the construction quality to avoid mistakes and omissions.
This paper will take a look at how to ensure the construction quality of reservation and embedment from the following aspects, based on typical examples, for your reference.
1 Material mobilization management system ▼ Raw material sample sealing system The construction party shall provide sealed samples for the materials and equipment included in the contract list of the construction party according to the materials with clear brands or manufacturers on the contract list to the Supervisor, the Cost Procurement Department and the Project Engineering Department of Party A one month before the commencement of work, which shall be signed and confirmed by the construction party, the Supervisor and Party A.
Two sets of sample sealing materials shall be used, one in the sample sealing room of Party A and the other in the sample sealing room of the general contractor.
Note: a.
It is required to unify the material sample sealing form; b.
Keep account records.
Example: · Embedded conduit (PVC intercepts the information section with spray code) · Electrical bottom box (PVC and metal 86 type box, equipotential bottom box) · PVC casing through the wall (intercepts the information section with spray code) · Steel casing through the wall (seals DN150 waterproof casing) and other ▼ raw material inspection application system 1) The first incoming materials shall be inspected.
The project supervision organization and the construction unit must notify the relevant professional engineers of the project engineering department of Party A to participate in the incoming inspection, The professional engineer of the project engineering department of Party A shall not be absent.
After the inspection is completed, the inspection shall be signed next to the signature column of the supervisor in the “Engineering Materials/Components/Equipment Approval Form”.
2) The construction unit applying for inspection of materials not entering the site for the first time shall apply for inspection according to the normal inspection procedures, the supervisor shall be responsible for acceptance, and the professional engineers of Party A’s Project Engineering Department shall randomly participate in the acceptance of materials entering the site at least twice a month.
Example: · Material mobilization inspection 2.
One time reservation and embedment of water heating ▼ Basic requirements for one time reservation and embedment of water heating 1.
Processing and fabrication: mechanical cutting, deburring, rust removal and anti-corrosion of inner wall.
2.
The inner wall of the casing shall be painted with anti-corrosion paint, and the outer wall of the casing shall not be treated.
3.
The welds of the water stop sleeve shall be uniform, and the thickness of the steel plate water stop ring shall be greater than 4mm.
4.
Both ends of the casing shall be sealed and protected with double-layer sealing tape.
5.
The continuous through wall system can adopt batch combination prefabrication method to ensure the accuracy of relative positioning between embedded casings.
Example: · Processing and manufacturing: mechanical cutting, deburring, derusting and anti-corrosion of the inner wall · The inner wall of the casing is painted with anti-corrosion paint, and the outer wall of the casing is not treated · The welds for the production of the water stop casing are uniform, The thickness of the steel plate waterstop ring is greater than 4mm.
The ends of both ends of the casing are sealed with double-layer sealing tape for protection.
The continuous wall penetrating system can adopt the batch combination prefabrication method to ensure the accuracy of the relative positioning between the embedded casings.
▼ Precautions for water heating reservation and embedment.
1.
The casing needs to be sealed with plastic film before installation.
The casing positioning is accurate and the spacing is accurate.
Install the sleeve according to the beam reinforcement binding progress to ensure that both ends of the sleeve are in close contact with the formwork, and the welded reinforcement around the sleeve is stable.
2.
After the completion of formwork erection, the coordinates of the casing shall be determined by snapping lines according to the casing points in the curing drawing and marked on the formwork.
3.
During casing embedding, it is strictly prohibited to gas weld the constructed reinforcement.
Due to embedded casing, reinforcement densification measures must be taken when the reinforcement spacing is increased.
4.
Before the construction of bottom reinforcement, place the prefabricated casing at the mark.
Four matching holes shall be drilled at the upper and lower 1/3 of the pipe, and the hole diameter shall be less than 2mm.
Lead wire shall be used to pass through the small hole on the casing to bind the surrounding reinforcement, and plastic film or wood plate shall be used to seal the pipe orifice.
5.
Prefabricated rectangular hole formwork can be used to reserve holes for three or more groups of adjacent risers, and the holes shall be filled by secondary pouring after the pipeline installation is completed later.
Example: · The casing shall be sealed with plastic film before installation, with accurate positioning and spacing.
Install the sleeve according to the beam reinforcement binding progress to ensure that both ends of the sleeve are in close contact with the formwork, and the welded reinforcement around the sleeve is stable· After the completion of formwork erection, the coordinates of the casing shall be determined by snapping lines according to the casing points in the curing drawing and marked on the formwork· During casing embedding, it is strictly prohibited to gas weld the constructed reinforcement.
Due to embedded casing, reinforcement densification measures must be taken when the reinforcement spacing is increased· Before the construction of bottom reinforcement, place the prefabricated casing at the mark.
Four matching holes shall be drilled at the upper and lower 1/3 of the pipe, and the hole diameter shall be less than 2mm.
Lead wire shall be used to pass through the small hole on the casing to bind the surrounding reinforcement, and plastic film or wood plate shall be used to seal the pipe orifice· Prefabricated rectangular hole formwork can be used to reserve holes for three or more groups of adjacent risers, and the holes shall be filled by secondary pouring after the pipeline installation is completed later.
▼ Requirements for casing polishing and identification after civil formwork removal 1.
During formwork removal, pay attention to the protection of the formed concrete around the reserved hole, and it is strictly prohibited to rough the hole edge.
2.
After the removal of the formwork, the interior of the casing shall be cleaned, the position and elevation of the reserved and embedded casing shall be rechecked, and the identification work shall be done (paper or paint can be pasted).
Example: · Pay attention to the protection of the formed concrete around the reserved hole when removing the formwork.
It is strictly forbidden to rough the hole edge.
Clean up the inside of the casing after removing the formwork.
Recheck the position and elevation of the reserved and embedded casing, and do a good job of identification (you can paste paper strips or paint).
3 Water heating secondary reservation and embedment ▼ Secondary reservation and embedment precautions.
1.
Prefabricate secondary embedded components in advance, and one-time embedment in masonry construction.
2.
Determine the processing materials of embedded components, casing slope and internal and external length of casing.
To prevent the insufficient length of the casing after the thermal insulation and plastering in the later period, it needs to be lengthened again.
3.
Attention shall be paid to the direction of embedding: the casing slope shall be toward the outside (the internal and external elevation difference shall not be less than 10mm).
Example: · Prefabricate the secondary embedded components in advance, and embed them once for masonry construction · Determine the processing materials, casing slope, and internal and external length of the embedded components.
To prevent the insufficient length of the casing after the thermal insulation and plastering in the later period, it needs to be lengthened again..
