The ventilation system can be divided into natural ventilation and mechanical ventilation, and mechanical ventilation can be divided into general ventilation and local ventilation. Harmful substances are concentrated in places, or ventilation methods in local areas where workers often move, such as fume hoods, universal fume exhaust hoods, atomic absorption hoods, etc.

The basic components of laboratory ventilation system

1. Ventilation terminal equipment: mainly including fume hood, universal exhaust hood, atomic absorption hood, blow-suction exhaust hood, etc.

2. Ventilation pipeline system: mainly include fans, air ducts, air valves, mufflers, waste gas treatment wet scrubber, etc.

Ventilation line:

1. The circular air duct has high ventilation efficiency but the diameter should not be too large. Due to the large temperature difference between indoor and outdoor in northern winter, FRP products can be used for outdoor pipes. For general laboratories, if the gas emitted indoors is not corrosive, galvanized iron sheets can be used for air pipes.

2. If the exhaust gas discharged from the laboratory is corrosive to a certain extent, the air duct should be made of PVC and FRP air ducts of corrosion-resistant materials; if the exhaust gas of the ventilation system contains strong acid (such as hydrochloric acid, nitric acid, etc.), the ventilation duct should be made of PP material duct. For no or only slight corrosion or customer requirements, stainless steel ducts can also be used.

Laboratory ventilation:

Place multiple fume hoods in the room or supply air to the room when the environment in the room requires it. The air supply volume is generally 70% of the exhaust air volume (the doors and windows can be supplemented by about 30%); the air supply system should be kept away from the fume hood as far as possible to avoid affecting the laboratory. The internal air conditioning, heating system, and supplementary air need to be pretreated before they can be sent to the laboratory.

There are several ways to supplement the wind:

• Make up the air through the indoor air conditioner.

• Place a section of air duct on the ceiling to connect it with the outdoors to achieve natural air supply.

• Use a supplemental air fume hood.

• Install a supplementary air system outside the ventilation system. If a supplementary air system is used, the supplemental air volume should be determined according to the airtightness of the room. The maximum supplementary air volume is 70% of the outlet air volume, and the minimum is 20%. The wind speed of the main duct can be set to 8m/s.

Harmful gas output system:

1. There are often many sources of chemical pollution that are not conducive to human health in the laboratory, especially harmful gases. It is very important to eliminate them. At the same time, energy is often consumed in large quantities, so the requirements for laboratory ventilation control systems are getting higher and higher, from early CV (constant air volume), 2-State (bistable), VAV (variable air volume) system, to State-of-the-art adaptive control systems - both safe and energy-saving. In short, the latest concept of the laboratory is to treat the entire laboratory as a fume hood. How to effectively control various intake and exhaust to achieve both safe and economical effects is crucial.

2. The commonly used exhaust equipment in the laboratory mainly include: fume hood, atomic absorption hood, universal exhaust hood, ceiling exhaust hood, table-top exhaust hood, etc. Among them, fume hoods are the most common. A fume hood is a ventilation device for the safe handling of harmful, toxic gases or vapors, and is used to capture, seal, and transfer contaminants and harmful chemical gases from spreading into the laboratory. The airflow in the fume hood is to suck the air in the laboratory into the fume hood through the exhaust fan, and after the polluted gas in the fume hood is diluted and discharged to the outdoors through the exhaust system, it can achieve low concentration diffusion.

3. The universal exhaust hood is the first choice for local ventilation: simple installation, flexible positioning, good ventilation performance, and can effectively protect the personal safety of laboratory staff; atomic absorption hoods are mainly suitable for various large-scale precision instruments, requiring positioning and installation , there are set ventilation performance parameters, which is also one of the factors that must be considered in the overall laboratory planning; the exhaust hood is mainly suitable for chemical laboratories, and it is indispensable in solving the overall ventilation requirements of such laboratories. one of the equipment.