What should be paid attention to when installing stainless steel welded ventilation pipes in convention and exhibition center?

As a large public building, the convention and exhibition center has the characteristics of large space, large flow of people, complex functional areas (such as exhibition hall, conference hall, rest area, equipment room, etc.) and diverse ventilation requirements. Safety, functionality, aesthetics and compliance should be taken into account when installing stainless steel welded ventilation pipes. The specific precautions are as follows:

First, the preliminary design and planning points

Adapting to the functional requirements of space

Different areas have different ventilation requirements: the exhibition hall needs to ensure air circulation and avoid odor accumulation; The conference hall should be combined with air conditioning system to control temperature and humidity and reduce CO concentration. Equipment rooms (such as power distribution room and computer room) need to be strengthened with heat dissipation and ventilation. When designing, the air volume and wind pressure should be calculated according to the regional function to ensure that the pipe diameter and direction match the tuyere layout.

Consider the demand for temporary exhibitions: temporary exhibitions are often held in the convention and exhibition center, which may involve the change of booths and the addition of equipment (such as temporary stage and lighting equipment). The pipeline layout needs to be adjusted to avoid damaging the pipeline or affecting the ventilation effect during later reconstruction.

Coordinate with the building structure

Convention and exhibition centers are mostly long-span steel structures or concrete frames. Pipeline installation needs to avoid bearing beams, columns, embedded parts, fire-fighting pipelines, cable bridges, etc. to avoid conflicts. The pipe hoisting in tall space (such as exhibition hall) needs to calculate the load bearing, so as to ensure that it is firmly connected with the roof truss and suspender.

If the pipeline needs to pass through the firewall and floor slab, it is necessary to reserve the fireproof plugging position, and then fill the fireproof materials (such as fireproof rock wool and fireproof sealant) according to the specifications to prevent the fire from spreading.

Second, material selection and welding quality control

Adaptability of stainless steel material

Choose the appropriate stainless steel brand: the environment of the exhibition center is mostly dry and clean, but some areas (such as the vicinity of the dining area and the exhaust of the bathroom) may be exposed to water vapor or slightly corrosive gases, so 304 stainless steel (general corrosion resistance) is preferred; If there is a higher anti-corrosion demand (such as near the swimming pool and disinfection area), 316 stainless steel can be selected.

Ensure material compliance: the wall thickness of the pipeline shall meet the design requirements (generally, the wall thickness of ventilation pipeline shall be ≥0.8mm, and the high-pressure system shall be thickened). Before entering the site, check the material certificate and factory inspection report to avoid using inferior or non-standard materials.

Welding technology and quality control

Adopt argon arc welding and other high-quality welding methods to ensure that the weld is smooth, free of pores, slag inclusion and cracks, and avoid air leakage (affecting ventilation efficiency) or insufficient pipeline strength. After welding, pressure test (such as air tightness test) is needed to detect whether there is leakage.

When welding stainless steel pipes, contact with carbon steel should be avoided (to prevent electrochemical corrosion). Welding tools and supports should be made of stainless steel or treated with anti-corrosion (such as zinc plating), and the weld should be polished smoothly to reduce airflow resistance and dust accumulation.

Third, the installation and construction safety and specification

Construction safety protection

Safety of aerial work: The height of the exhibition center is high, and qualified lifting equipment (such as cranes and elevators) should be used for pipeline hoisting. Operators should fasten their safety belts and set up edge protection and warning signs to avoid falling risks.

Management of hot work: Welding is a hot work, so it is necessary to apply for a hot work permit, equip with fire extinguishers, fire blankets and other equipment, clean up the surrounding combustible materials (such as thermal insulation materials and decorative fabrics), and arrange special personnel to monitor if necessary to prevent fire.

Coordination of cross-operation: The construction of the convention and exhibition center may involve the cross of civil engineering, fire fighting, electromechanical and other jobs, so it is necessary to plan the construction sequence in advance to avoid the conflict between pipeline installation and other projects (such as collision and space occupation), and pay special attention to protecting the installed fire alarm and sprinkler systems.

Pipeline fixation and seismic requirements

Stainless steel pipes are heavy, and the spacing between supports should conform to the specifications (for example, the spacing between supports of horizontal pipes is ≤ 1.5m, and the spacing between vertical pipes is ≤ 2m). Rubber pads or stainless steel gaskets should be placed between supports and pipes (to avoid scratching pipes and reduce vibration and noise).

Seismic design should be considered in large-scale convention and exhibition centers, and anti-seismic supports and hangers should be added to pipeline supports, especially in earthquake-proof areas, to ensure that the pipeline will not fall off and deform during vibration and avoid secondary disasters.

Fourth, coordination with other systems

Linkage with air conditioning and fire fighting system

Ventilation pipes should be connected with the central air conditioning system to ensure the rationality of fresh air supplement and return air circulation and avoid the increase of air conditioning energy consumption due to excessive pipeline resistance. For example, the ventilation of the exhibition hall needs to cooperate with the air supply outlet of the air conditioner to evenly distribute the cold and hot air, so as to enhance the somatosensory comfort.

Compatibility with fire smoke exhaust system: some ventilation pipes can be designed as dual-purpose systems of "ventilation at ordinary times and smoke exhaust in case of fire", which should meet the requirements of smoke exhaust temperature (stainless steel pipes should withstand high temperature above 280℃) and be linked with fire control center to ensure automatic switching function in case of fire.

Harmonious with the beauty of decoration.

The exhibition center pays attention to the overall beauty, and the exposed pipes should be kept straight and neatly arranged. After the welds are polished smoothly, they can be brushed or mirrored. In the concealed area (such as the ceiling), the pipeline needs to reserve enough space with the ceiling keel and decorative panel to avoid affecting the decoration effect or access.

The tuyere installation should be consistent with the style of the wall and ceiling. Stainless steel or the same color tuyere should be selected, and it should be located away from key areas such as the exhibition area and the podium to avoid direct air blowing on personnel or exhibits.

V. Post-detection and compliance

Performance testing and debugging

After installation, carry out ventilation test to ensure that the deviation between the actual air volume and the design value in each area is less than or equal to 10%; Check the pipeline resistance and air leakage rate (air leakage rate ≤3% as required by national standards) to avoid energy waste or insufficient ventilation caused by air leakage.

When debugging, automatic control systems (such as CO sensors and temperature and humidity sensors) are combined to ensure that the air volume of the pipeline can be automatically adjusted according to the actual demand (such as increasing the fresh air volume at the peak of people flow).

Compliance and document retention

It shall conform to the national standards such as Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering (GB 50243) and Code for Fire Protection Design of Buildings (GB 50016), and the fire-fighting related parts shall pass the fire-fighting acceptance.

Keep complete construction data, including design drawings, material certificates, welding inspection reports, pressure test records, concealed works acceptance sheets, etc., to provide a basis for later maintenance and transformation.

summary

The installation of stainless steel welded ventilation pipes in convention and exhibition center should be controlled from five core dimensions: functional adaptation, material quality, construction safety, system coordination and compliance. It should not only meet the basic needs of large-space ventilation, personnel comfort and fire safety, but also take into account the aesthetic and flexible operation requirements of convention and exhibition center to ensure the long-term stable operation of the pipeline system and provide environmental protection for the smooth holding of large-scale activities.