What should be paid attention to when the galvanized air duct is fixed on the external wall during installation?

A complete set of precautions for installation and fixation of galvanized air duct external wall (anti-falling, anti-corrosion, anti-seepage and weather resistance)

1. Structural fixation and bracket selection (the most critical)

It is strictly forbidden to fix it on the external wall insulation layer, external wall coating layer and ceramic tile surface layer. It must be pierced through the insulation layer and fixed to concrete structure beams and columns and solid brick walls. It will only fall off if it is hung on the insulation layer for a long time.

Support material specification

The exterior wall must be made of hot-dip galvanized angle steel/channel steel, the thickness of which is one more than that of the interior, and thin materials and non-standard angle iron are not used.

Lead screws and expansion bolts are all hot-dip galvanized or stainless steel to prevent outdoor rust and fracture.

Strong wind and high-rise external wall: the spacing between supports is denser than indoor, and the conventional 2.5m is changed to 1.5 ~ 2m.

Anchorage mode

Concrete wall: use extended expansion bolts and chemical anchor bolts, with sufficient burial depth. Short expansion and nail fixing are strictly prohibited.

Hollow brick/aerated block: it can't be expanded directly, so it must be reinforced by pre-embedded steel plate and through-wall pulling screw.

Second, the special anti-corrosion (galvanized duct exterior wall must be done)

Location of damaged zinc coating by air duct incision, welding seam and punching hole: brush antirust paint+topcoat twice.

All supports, cutting sections and welding points shall be derusted and painted with anti-corrosion paint, and then painted with exterior wall paint of the same color.

Rubber pad/anti-corrosion wooden bracket is added between galvanized air duct and carbon steel bracket to avoid electrochemical corrosion, rust and perforation.

Exterior air duct is strictly forbidden to be exposed and damaged, and the damaged position should be repaired in time to prevent rain from corroding the inner wall from the damaged position.

Three, waterproof, rainproof, waterproof requirements

Exterior wall hole:

The gap between the air duct and the wall is sealed with fireproof sealant+waterproof mortar, and the outer side is sealed with weatherproof sealant, so as to make the water stop slope low outside and high inside to prevent rainwater from flowing backwards into the room.

The overall installation of air duct shall be done with drainage slope:

According to * * 0.5% ~ 1% * * slope to the outdoor or drainage point, to avoid rainwater accumulated in the pipe and flowing back into the computer room and indoor.

Rainproof elbows and rainproof caps shall be added at the upper and open positions of the air duct to prevent rainwater and fallen leaves from pouring into the pipe.

Flange joints are all sealed with weather-resistant sealant for external walls, which is windy and rainy outdoors, and only cushion pieces are prone to rain and air leakage.

Fourth, wind resistance, anti-shaking, anti-falling

High-rise, windward exterior wall: horizontal and vertical anti-sway brackets must be added, not just vertical hangers.

Elbows, tees, reducer, through-wall entrances and exits shall be provided with bearing supports separately, and it is not allowed to borrow the main pipeline.

Vertical external wall riser: each floor is provided with a bearing bracket, and a hoop is added in the middle to prevent strong wind from swinging and pulling the interface.

Multiple air ducts are arranged side by side: independent supports are stressed independently, and cross arms are not shared, so as to avoid mutual traction and deformation caused by wind loads.

Five, flange and interface outdoor strengthening

All flanges of the external wall: thickened gaskets, bolts are fully installed and tightened diagonally, and the outer side is fully covered with weatherproof sealant.

Minimize outdoor flange joints, prefabricate the whole section, minimize outdoor splicing and reduce air leakage and water leakage points.

The external wall interface of the fan must be equipped with flexible joints to isolate vibration and avoid loosening the bracket and flange due to perennial vibration.

Six, construction safety and appearance specification

Safety belts must be hung, scaffolding or hanging baskets must be erected for aerial work on external walls, and single-point work suspended is prohibited.

The air ducts shall be arranged horizontally and vertically, the stay wires shall be installed, the look and feel shall be straight, and the supports shall be neat and unified.

Avoid external wall lightning protection, gas pipelines, strong and weak electricity pipelines, keep a safe distance, and do not occupy fire exits.

Seven, the three most prone to problems.

The bracket is only fixed on the insulation layer of the external wall, and it cracks and falls off in the later stage.

Incisions and welds will rust out in a year or two if they are not repaired for corrosion protection.

The hole through the wall is not waterproof and water-tight, and rainwater flows into the room along the air duct and leaks.