Heating and sanitary equipment pipeline installation and construction technology

1 Scope This process standard is applicable to indoor and outdoor heating and sanitary equipment pipeline installation projects in civil and general industrial buildings. ​

2 Construction preparation 2.1 Material and equipment requirements

2.1.1 Heating and sanitary equipment, steel, pipes, pipe fittings and ancillary products should be carefully inspected after entering the site and before use. They must meet the relevant quality and technical requirements of national or ministerial standards, and have product certification certificates. ​

2.1.2 Various connecting pipe fittings shall not have blisters, cracks, partial buckles, random buckles, incomplete threads and inaccurate angles. ​

2.1.3 The appearance of various valves must be regular and without damage, the valve body must be tight, and the valve stem must not be bent. Tightness tests must be conducted in accordance with design requirements or construction specifications and regulations before installation.

2.1.4 The quality of asbestos rubber mats, oil and linen, linen, cement, electric and gas welding rods, etc. must meet the design and specification requirements. ​

2.2 Main Machinery and Tools 2.2.1 Machinery and Tools: Threading machine, grinding wheel saw, bending machine, grinder, electric welding machine, bench drill, electric hand drill, electric hammer, electric hydraulic pump, etc. ​

2.2.2 Tools: Wire plate, round wire plate, pipe wrench, chain pliers, adjustable wrench, hand saw, hand hammer, sledgehammer, chisel, twisting chisel, hemp drill, screw plate, pressure table, bench vise, Wire cutters, screwdrivers, gas welding tools, etc. ​

2.2.3 Measuring tools: spirit level, steel tape measure, wire drop, welding joint detector, caliper, small wire, etc. ​

2.3 Operating conditions

2.3.1 Arrange appropriate on-site work sites, work sheds, and material warehouses according to the construction plan. When operating in the pipeline layer, basement, and trench, low-voltage lighting must be turned on. ​

2.3.2 Prepare various reserved holes and pipe grooves in accordance with the progress of civil construction. Stable installation of various types of steel supports, elevator frames and embedded casings, pouring of floor slab holes, and plugging of wall holes should be completed before the start of civil construction and decoration projects. ​

2.3.3 Before each prefabricated processing project is carried out, the specifications, models, quality and quantity of the required materials and equipment must be confirmed to be qualified and fully prepared according to the installation survey sketch and material plan, and transported to the site.

3 Operation process

3.1 Process flow: (See process on the next page)

3.2 Pipe prefabrication processing:

3.2.1 Pipe thread connection:

3.2.1.1 Pipe breaking: According to the on-site surveying and mapping sketch, draw a line on the selected pipe and break the pipe according to the line. ​

Water flow test

a Use a grinding wheel to saw off the pipe, place the pipe on the grinding wheel saw caliper, align it with the drawn line and clamp it firmly, and then cut the pipe. When breaking the pipe, press the handle with even force and do not use too much force. After breaking the pipe, clean the iron film and burrs on the section of the pipe mouth. ​

b To cut off the pipe by hand, the pipe should be fixed in the pressure clamp of the pressure case, align the saw blade with the drawing line, push the saw with both hands, the saw blade should be kept perpendicular to the axis of the pipe, the force of the push and pull saw should be even, and the saw kerf should be cut to the bottom , do not twist or break to prevent the cross-section of the tube from deforming. ​

3.2.1.2 Thread threading: Thread the broken pipes in batches according to the diameter of the pipe. Generally, the threads are set twice for pipe diameters of 15~32mm, three times for pipe diameters 40~50mm, and 3~4 times for pipe diameters above 70mm. It is appropriate. ​

a Use a threading machine to thread, clamp the pipe on the threading machine chuck, leave an appropriate length to clamp the chuck, align the plate code, install the die, align the appropriate position of the scale according to the pipe diameter, and tighten Fix the trigger, align the lubricant tube with the thread head, turn on the machine and push the plate, wait until the thread buckle reaches the appropriate length, and then gently release the trigger. ​

b Use the manual threading board to thread, first loosen the fixed trigger, return the threading plate plate to zero, install the die according to the sequence number, align the plate with the required scale, tighten the fixed trigger, and place the pipe In the pressure pliers of the pressure case, leave an appropriate length for clamping, and gently insert the thread plate into the pipe to make it moderately tight. Then push the thread plate with both hands, put on 2 to 3 buckles, and then stand to the side to turn the sleeve. Use even force on the wire plate. When the thread fastener is about to be set, gently release the trigger, turn on the machine and withdraw the board, keeping the thread fastener to have a taper. Please refer to Table l-l for the pipe thread length dimensions.

3.2.1.3 Assemble pipe fittings: According to the on-site surveying and mapping sketch, assemble the pipe fittings that have been threaded. ​

a When assembling pipe fittings, the required pipe fittings should be brought into the pipe thread buckle, and the tightness should be tested (generally, it is appropriate to bring in 3 buckles by hand), apply lead oil on the thread buckle, wrap it with hemp, bring it into the pipe fitting, and then use the pipe Use pliers to tighten the pipe fittings so that 2 to 3 buckles of the threads are exposed. Remove the hemp heads, wipe off the lead oil, and put the numbers in the appropriate positions for straightening. b Select an appropriate pipe wrench according to the diameter of the pipe fittings (see Table 1-2). ​

3.1.2.4 Straightening of pipe sections: Straighten the pipe sections with installed pipe fittings before installation. ​

a Apply lead oil to the threaded joints of the pipe sections where the pipe fittings are installed, and connect two or more sections. When connecting, do not just pay attention to the direction of the reserved opening, but also take into account the curvature of the pipe. After aligning each other, turn the direction of the reserved opening. Appropriate parts and maintain integrity.

b After the pipe sections are connected, before straightening, the pipe diameter, reserved opening direction, and diameter reduction part must be checked according to the design drawings to see if they are correct. ​

c The straightening of the pipe section should be placed on the pipe adjusting rack or pipe adjusting platform. Generally, it is suitable for two people to operate. One person will visually inspect the end of the pipe section, and the other will hit the bend with a hammer. While beating, observe, until the pipe section is straightened. until there is no bend, and mark the connection point between the two pipe sections, remove one or several sections, and then connect another section or sections until the adjustment is completed. d. For pipes that are too bent or have large diameters at the connection points of pipe fittings, oven or gas welding can be used to heat them to 600~800℃ (fire red). Place the pipes on the pipe rack and rotate them continuously, using the weight of the pipes. Make it straight, or use a wooden pad to straighten it with a hammer at the heated place. After straightening, keep turning it before cooling. When the temperature drops to the appropriate level, apply engine oil to the heated place. ​

All screws that have been heated and straightened must be marked, removed, re-coated with lead oil and wrapped with hemp, and then the pipe section is aligned with the mark and tightened.

e When straightening the pipe section with the valve installed, the valve cover should be removed first, and the valve should be firmly padded before beating to prevent the valve body from cracking. f Galvanized carbon steel pipes are not allowed to be straightened by heating. ​

g When straightening the pipe section, no damage to the pipe is allowed. 3.2.2.1 Where pipe sections are connected by flanges or pipes are connected by flange valves, standard flanges must be selected according to the design requirements and working pressure. ​

3.2.2.2 The diameter and length of the connecting bolts of the flange plate should comply with the specification requirements. When tightening the flange plate bolts, they should be tightened symmetrically. The exposed threads of the fastened bolts should be 2 to 3 buckles, and should not be larger than half of the bolt diameter. one.

3.2.2.3 Flange connection gasket. Generally, water supply pipes (cold water) use rubber gaskets with a thickness of 3mm. Heat supply, steam, and domestic hot water pipes should use asbestos rubber gaskets with a thickness of 3mm. The gasket must be concentric with the pipe diameter and must not be offset. ​

3.2.3 Pipe welding 3.2.3.1 According to the design requirements, steam pipes with a working pressure above 0.1MPa, heating pipes with a general diameter above 32mm, and fire protection pipes in high-rise buildings can be connected by electric or gas welding. ​

3.2.3.2 When welding pipelines, measures should be taken to prevent wind, rain and snow. The ambient temperature of the welding area is lower than -20°C. The welding joint should be preheated. The preheating temperature is 100~200°C and the preheating length is 200~250mm. ​

3.2.3.3 Generally, the welding of pipelines is of matching type and combination. If there is no requirement in the design, electric welding shall comply with the provisions of Table 1-3, and gas welding shall comply with the provisions of Table 1-4.

3.2.3.4 Before welding, the axes of the two pipes should be aligned, and the ends of the network pipe should be spot welded securely. If the pipe diameter is below 100mm, three spots can be spot welded. If the pipe diameter is above 150mm, it is advisable to spot weld four spots.

3.2.3.5 If the wall thickness of the pipe is more than 5mm, the welding joint at the pipe end should be beveled. If metal laser welding is used to process the pipe slope, the oxide scale on the bevel surface must be removed, and the uneven areas that affect the welding quality must be smoothed (Fig. l-2).

3.2.3.6 When welding pipes and flanges, the pipes should be inserted into the flange first, and then spot welded at 2 to 3 points, then aligned and leveled with a square before the direction can be welded. The flange should be welded on both sides, and the welds on the inside of the flange should not be Protrude the flange sealing surface (Figure l-3). ​

3.2.4 Pipe socket connection

3.2.4.1 Cement twist: generally used for socket connections of indoor and outdoor cast iron drainage pipes. ​

a In order to reduce the twisting and fixing of the gray holes, some pipes and fittings can be pre-twisted. Before twisting the gray holes, the pipes and fittings should be checked for cracks, blisters and other defects, and the pipes and fittings should be pre-arranged to check whether there are any errors in the dimensions. , whether the gray annular gap of the socket is qualified.

b When connecting pipes and pipe fittings, they can be placed on temporary fixing frames. The pipes and pipe fittings should be inserted with the socket upward and the spigot downward according to the requirements of the drawing, and twist the gray opening. ​

c When twisting the gray joint, first use a hemp drill