1. SCOPE OF WORK (前言)
Furniture supplier shall be responsible for final connection of Fume Hood, canopy hood, vents of acid, flammable cabinets, and shall be communicating with HVAC contractor for air exchange volume, air exchange rates to meet lab safety requirement.
实验室家具承包商将负责抽风柜，排风罩和酸碱柜等排风点的最后连接，并负责和空调及排风系统的承包商确定实验室区域的排风量，换气频率等具体技术要求，确保实验室的安全。
2. GENERAL (综述)
2.1 The laboratory exhaust system includes exhaust duct works, exhaust fan, laboratory fume hood exhaust, laboratory canopy hood and cabinets needed venting.
实验室排气系统包括排气管路、排气风机、实验室通风柜管道、实验室排风罩和特殊存储柜的排气管道。
2.2 Some specified scrubber(s) to treat toxic or hazardous gases should be provided at the end of exhaust system and the concentration of exhaust gas should be meet the CCIQ policy. This part shall be responsible by HVAC contractor.
对有毒、危险气体的排气管路末端有空气洗涤塔，最终气体排放浓度要满足CCIQ的相关标准。此部分将有空调及排风系统的承包商负责。
2.3 There shall be 10 air changes per hour of ventilation in wet laboratories and 8 air changes per hour of ventilation in dry laboratories. With approval, airflow may set back to 6 air changes per hour when space is unoccupied.
化学实验室空气换风量至少为10次每小时，仪器室至少为8次每小时。如经过同意，当实验室无人时，可以将换气量降为6次每小时。
2.4 Hood exhausts may be manifolded together. Exhausting highly reactive, incompatible or highly toxic materials shall not be manifolded and exhausted directly to the outside. Special exhaust cleaning system shall be provided in dedicated exhaust system.
通风柜排气管路可以连接在一起。产生高反应活性、性质不相容、强毒性气体的通风柜管路不能连接在一起，并且直接排除室外。某些排气管路需要有清洗装置。（如高氯酸通风柜）
2.5 Acid and solvent storage cabinets need to be vented. These cabinets shall be connected directly to an exterior exhaust duct above the fume hood trim or balancing damper.
酸柜和溶剂柜根据情况需要有通风装置。可以直接连接到通风柜排气系统中去。
3. FUME HOOD (通风柜)
Bench-type fume hood is the main type in CCIQ laboratory.
台式通风柜是CCIQ实验室主要的通风柜。
Fume hood face velocity shall be 100fpm (0.5m/s), actual exhaust volume shall be 900 m3/h to 1150 m3/h according to SEFA & AHRAE recommendations. Canopy hood shall have 600m3/h each outlet to ensure weak negative exhaust. The volume of other exhaust outlet for vented cabinet, vacuum oven etc. should comply with equipment requirement.
通风柜表面风速为0.5m/s，根据SEFA和AHRAE的要求，通风柜排气量在900 m3/h 到 1150 m3/h之间。每个排气罩排气量在600m3/h。另外，在特殊存储柜和仪器上方排气罩的排气量满足设定的要求。每个排气口保持负压。
4. EXHAUST FAN (排气风机)
4.1 Exhaust fan should be sized to provide enough suction and flow velocity at each of the exhaust point in the laboratory
排气风机的大小要满足足够的风量和表面风速。
4.2 Each main exhaust pipe shall have one exhaust fan.
一个风机控制一个主要的排气管道。
4.3 Exhaust fans shall be a belt driven, centrifugal type
排气风机为皮带式，离心风机。
4.4 Exhaust fans shall be installed on the roof of the building.
风机安装在房顶。
4.5 Exhaust fans shall be UPVC or equivalent material with chemical resistant.
风机由UPVC或类似的材料建造。
5. EXHAUST DUCT (排气管道)
5.1 Exhaust ducts shall be made of PVC or equivalent
排气管道由PVC或类似的材料建造。
5.2 Mechanical volume control damper shall be available at each exhaust point to enable easy balancing.
每个排气点上由机械控制阀门来保持气压平衡。
5.3 These mechanical dampers shall be easily accessible for maintenance.
这种控制阀门易维护。
5.4 Ducts shall be suitably welded or sealed for leakage.
管路有合适的焊接和密封，来保证不泄漏。
5.5 Provision should be added to prevent possible leakage of water in to the duct system thus into the laboratory.
要保证水不会渗透到管路里，从而进入实验室。
6. SCRUBBER SYSTEM (气体净化塔)
6.1 This system is used for the chemical laboratory and its functions to remove harmful vapors from the exhausted air by means of water or specified reagent dilution.
化学实验室排气系统需要有空气净化塔，通过水和特殊试剂对排气中有害气体进行洗涤。
6.2 Scrubber system often includes spray system, absorbing system and collection system. The exhaust gas is led to the inlet of the system and contacts with the down-steam so that the gas can be soluble or be capable of reacting chemically with the scrubbing liquid. At last, the liquid should be collected in collecting section.
净化系统包括布水装置、吸收系统和收集系统。排气引入净化塔下部，和上面喷洒的溶剂接触，气体溶解或与溶剂产生化学反应，最后溶剂被收集装置收集。
6.3 The degree of solubility depends on the type of gas, its concentration (more fraction or vapor pressure), the system pressure, the type of absorbing liquid, and the liquid temperature.
溶解程度和气体种类、浓度、系统压力、吸收液种类、温度等多种条件有关。
6.4 If liquid reaches equilibrium within the scrubbing media, it cannot absorb additional gas. To prevent equilibrium from occurring and drastically reducing the removal efficiency, fresh liquid is introduced and contaminated liquid is withdrawn from the system.
如果溶剂在吸附材料表面的达到平衡，溶剂就不能再吸附多余气体。为了避免这一现象，新的溶剂要引入，污染的溶剂要排除。
6.5 Since it is the liquid that is absorbing the gas, a means of extending the liquid surface must be provided. This is why an effective scrubbing media is needed. By providing a good scrubbing media over which the liquid is spread, a greater area of contact can be achieved and this area of gas-liquid contact is the area of the scrubbing media.
因为是溶剂吸附了气体，所以气液接触面就要大。所以，吸附材料要好，气－液接触表面在吸附材料上有很大的延伸面。