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Veteran workers share their experience; explanations on water supply and drainage methods – you’ll learn about outdoor water supply and drainage systems, pipes, inspection wells, and manhole covers； For outdoor drainage pipes with a diameter greater than 500, reinforced concrete pipes are used; those with a diameter of 500 or less use UPVC pipes or double-wall corrugated pipes. Composite manholes are used for outdoor water supply and drainage inlets, and the load-bearing standards for these manholes are as follows: lightweight for green spaces, standard for sidewalks, and heavy-duty for fire access routes. In the main pedestrian areas for commercial use, decorative manhole covers are used. The water supply system’s outdoor fixtures for landscaping are installed using sprinkler-type manholes buried underground; specialized landscaping faucets are employed, and PPR or PE pipes are used for the water supply. On sites developed in phases, the main outdoor water supply pipes for each phase are equipped with valves to facilitate maintenance. For the drainage system, inspection wells and rainwater inlets are constructed using sand bricks. The use of red bricks is prohibited. During construction, inspection wells must be covered with cast-in-place concrete temporary covers. For the drainage systems in valve wells, either drain pipes should be used, or a cushion layer of medium-coarse sand and gravel with a thickness of more than 200 mm at the bottom of the well should be employed; concrete cushion layers are not allowed. Indoor water supply and drainage: Selection of water supply pipes – for concealed installation indoors, PPR pipes are used; the cold water pipes operate at 1.6 MPa, while the hot water pipes operate at 2.0 MPa, with heat fusion used for connections. Exterior wall installation or exposed installation in pipe shafts: steel-plastic water supply pipes ； The water supply pipe connections provided in the unfinished houses must protrude 10 mm above the plaster surface; moreover, one standard faucet is to be pre-installed in each household. The public cleaning water faucets reserved for residential use are installed in the meter wells, with at least one such faucet provided on every two floors. When laying the hot and cold water supply pipes beneath the floor slab in residential buildings, the vertical distance between these pipes and the wall should be 200 mm, with a minimum of 100 mm not being allowed. When delivering a raw building to the owner, it is necessary to use blue and red lines to indicate the paths of the hidden hot and cold water pipes on the floor and walls, and labels such as “hot water pipe” and “cold water pipe” should be placed along those paths to help homeowners keep this in mind during renovation. When delivering a renovated building, it is required to use methods such as sticking plastic markers to indicate the locations of the hidden pipes. Drainage system: Ordinary U-PVC drainage pipes are used for indoor drainage pipes and exterior wall drainage pipes. For caisson-type kitchens and bathrooms, side-mounted floor drains should be installed right next to the structural slab (direct-floor-drain installations can only be considered if that is not feasible); direct-floor-drain openings should also be provided at each layer of the filling material. For a mezzanine drainage system designed without a drop plate, fittings with inspection ports should be used. The lowest elevation of the drainage cross-pipe installed under the lower kitchen and bathroom ceiling should reach H+2.40; it is strictly prohibited to be lower than H+2.25. Toilet floor drains, washing machine floor drains, bathtub drain pipes, sink drain pipes, and vegetable washing basin drain pipes: equipped with S-shaped trap; balcony drainage floor drains are equipped with P-shaped trap. The private garden on the first floor, as well as the public water meter well, should be equipped with drainage facilities. For fixture installation, sink faucets, wall-mounted sinks, and vegetable washing basins all use corner valves as well as hot and cold water faucets connected by hoses; raw-house sinks and wall-mounted sinks are equipped with pre-installed hot and cold water connections. Installation height: The elevation of the water supply inlet for gas water heaters is H+1.15; for electric water heaters, it is also H+1.15. The elevation of the shower faucets in public restrooms is H+0.80; that of bathtub faucets is H+0.65; the elevation of laundry machine faucets is H+1.15; the elevation of the faucets for showers is also H+1.15. The elevation of their fixing supports is H+1.65. The elevation of the cold and hot water inlets reserved for countertop sinks, column-mounted sinks, and vegetable washing sinks (i.e., the elevation of the angle valves) is H+0.45. The elevation of the angle valve for the toilet’s water supply is H+0.15, with the horizontal distance between the center of the angle valve and the center of the toilet being approximately 140 mm. Cold and hot water pipes: The horizontal distance between the pipe ends is 150 mm; installation height: the cold water horizontal pipes are at a height of 0.25 meters above the finished floor, while the hot water horizontal pipes are at a height of 0.40 meters above the finished floor. Pre-embedding: Pipes are embedded or pre-arranged within the floor slabs. Requirements: Before pouring the concrete, appropriate PVC pipes (filled with sand inside) should be tied to the structural rebar at a distance of about 10 mm from it, and fixed in place using wire; one point every 1 meter. It is not allowed to cut grooves later for installing these pipes. The pre-embedded pipe grooves must be uniform and straight, and they must not be placed within the layers of the building structure. Construction requirements for internal water supply grooves in walls: When located within brick walls, a groove of appropriate depth should be pre-formed during wall construction; when located within aerated block walls, marking should be done first on the wall surface, after which the groove is created using mechanical methods. Preparation of openings in floor slabs: Use galvanized steel sleeves of appropriate diameter (equipped with handles). After both ends of the sleeves are sealed, fix them to the formwork using wire and nails, etc., and remove them immediately once the concrete has started to set. Water heater exhaust duct sleeve: A thin-walled steel pipe with DN150 diameter is reserved, with the center elevation of the pipe at H+2.40. Air conditioning sleeves: Reserved in reinforced concrete walls and beams – DN80 PVC pipes are used for this purpose; reserved in masonry structures – pre-made concrete sleeves made of DN80 U-PVC pipes are utilized. Installation height: For split-type air conditioners, the top elevation of the sleeve is 420 MM above the ceiling, while for cabinet-type air conditioners, the center elevation is H+0.15. Ventilation fan sleeve in the bathroom: It should be pre-installed in reinforced concrete walls and beams, using DN100 PVC pipes; for masonry structures, prefabricated concrete sleeves made of DN100 U-PVC pipes are used. The installation height of the sleeve is such that the center elevation of the sleeve is at H+2.40. Hood exhaust duct sleeve: A DN150 PVC pipe is reserved, with the center elevation of the pipe set at H+2.50. The distance from the center of the holes in the fixtures’ mounting plates to the finished wall surface (i.e., the surface of the ceramic tiles) is as follows (based on the dimensions of popular brand fixtures on the market): 350x40 mm for bathtubs (on the sides and near the faucet), 305 mm for toilets, 205 mm for wall-mounted sinks, 150 mm for countertop sinks, 150 mm for floor drains (except those in kitchens and showers), 150x150 mm for shower floor drains, and 650 mm for kitchen floor drains. For other roofs, whether premium or non-premium, as well as green roofs, the construction requirements for side drainage outlets specify that the surface of their base structure should be 10 mm thick ； Construction requirements for floor-mounted drains in bathrooms, kitchens, balconies, and corridors: their surface should be in close contact with the structural floor slab. Fixing of roof pipe supports: Angle iron supports are embedded in separate concrete pedestals (dimensions: 300mm*200mm*150mm), and then fixed using galvanized pipe clamps; it is prohibited to fix them directly to the roof structure or waterproof layer using expansion bolts. Temporary water supply and drainage during construction: For water supply pipes with a diameter of 50 mm or more, steel pipes are used, while for pipes with a diameter less than 50 mm, UPVC water supply pipes are employed. The sedimentation tank dedicated for car washing at drainage outlets must have an effective volume of more than 2 m². Drainage pipes for road use should be made of reinforced concrete, and open drainage ditches must be constructed from bricks, with internal dimensions of 250mm*200mm. A sedimentation tank with a capacity of more than 0.5 m³ should be installed every 50 meters; otherwise, discharge into the official drainage system is prohibited. Auxiliary materials for outdoor valve connections: Bolts – made of galvanized material; Gaskets – corrosion-resistant plastic gaskets or asbestos gaskets; Steel flanges – conforming to national standards, and must be coated with two layers of anti-rust paint before installation. Pipe fixation: Pipe clamps are finished products made of galvanized material; angle steel comes from national standard series, and it must be coated with an anti-rust paint before processing. Anti-corrosion method for indoor hot-dip galvanized fire protection steel pipes: (in order of construction) ； Primer: Apply one coat of epoxy paint (gray); dry film thickness: 30 µm. Topcoat: Apply one coat of alkyd enamel (red); dry film thickness: 35 µm. Topcoat: Apply one more coat of alkyd enamel (red); dry film thickness: 35 µm. Protection of finished products: The top of the water supply pipes buried in the pre-installed pipe grooves in the floor slabs must be covered with a cement mortar protective layer of at least 15 mm thick. Water supply and drainage risers: After installation, they must be covered with ordinary plastic film to prevent contamination by mortar, paint, etc., so as to be delivered in good condition. Equipment, valves, fire extinguishers: Protective measures must be resistant to impact and contamination.