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Temperature
The temperature in A Clean Room refers to the temperature of the indoor ambient air, expressed in degrees Celsius (°C). Glass thermometers, digital (including thermocouples, thermal resistors, Semiconductor) thermometers can be used to measure the indoor temperature, or dry-bulb hygrometers, digital hygrometers, and thermometers attached to anemometers can be used. The thermometer test range is required to be between -10°C and 50°C with an accuracy of +0.3°C.
Note:
When reading, the line of sight must be perpendicular to the ruler and at the same level as the liquid column surface.
When reading, do not touch the ruler or remove the thermometer from the socket, and do not hold the temperature bag by hand to read, otherwise it will cause a huge error.
Relative humidity
Humidity refers to the moisture content in the air. There are two ways to express it:
1.Absolute humidity: Unit The mass of water vapor contained in a volume of air;
2.Relative humidity (RH): The ratio of the actual water vapor pressure in the air to the saturated water vapor pressure under the same temperature conditions, expressed in %. Humidity is generally expressed in relative humidity. Relative humidity can be measured using a dry-bulb thermometer, a lithium fluoride dew point hygrometer, or a capacitive digital hygrometer. The hygrometer test range should be between 12% and 99%, with an accuracy of +0.3%. For more information, please refer to the instruction manual of the instrument used.
air velocity
Indoor and outdoor temperature differences, pressure differences, artificial ventilation, air conditioning, indoor heat sources, etc. can all cause air flow, which has the same dilution and diFFUsion effect on pollutants as outdoor air flow. Air velocity can be measured using a hot-bulb anemometer and a hot-wire anemometer. The anemometer test range should be between 0.01 m/s to 20m/s, with an accuracy of +5%. For usage, please refer to the instrument manual.
Fresh Air volume
1.Principle: The tracer gas concentration decay method is used. An appropriate amount of tracer gas is introduced into the room to be tested. Due to the exchange of indoor and outdoor air, the concentration of the tracer gas decays exponentially. According to the change in concentration over time, the indoor fresh air volume is calculated.
2.Instruments and materials
Pocket or lightweight gas concentration meter.
Ruler, swing fan.
Tracer gas: colorless, odorless, non-toxic in concentration, safe, low environmental background, easy to sample, and easy to analyze.
| Gas name | Toxicity level | Environmental background level, mg/m3 |
| Carbon monoxide | Human inhalation 50 mg/m3 for 1h, no abnormality | 0.125~1.25 |
| Carbon dioxide | Maximum allowable concentration in workshop 9000 mg/m3 | 500 |
| Sulfur hexafluoride | Mice inhalation 48000 mg/m3 for 4h, no abnormality | Below detection limit |
| Nitric oxide | Mice LC501090 mg/m3 | 0.4 |
| Octafluorocyclobutane | Rats inhalation 80% (20% oxygen), no abnormality | Below detection limit |
| Bromotrifluoromethane | Workshop standard 6100 mg/m3 | Below detection limit |
Selection, layout and maintenance of professional production equipment
a.Choose production equipment and related equipment with less dust generation, especially pay attention to the dust generation of active parts.
b.Choose production equipment or equipment with less dust impact Interface equipment.
c.Water, gas, and medicine used in production are often the cause of pollution, so filtering devices should be equipped.
d.When planning the configuration space of each equipment, it is advisable to consider the structure that is not easy to accumulate dust in advance, and plan each according to the principle of easy cleaning.
e.Equipment that is easy to generate pollutants, such as vacuum pumps, should be installed outside the clean room or in the return air area, and exhaust pipes should be installed for exhaust.
f.When setting up water supply pipelines, gas pipelines and electrical systems, their structures must take into account easy cleaning and not easy to accumulate pollutants.
g.Production and related equipment should be cleaned regularly to avoid the accumulation of dust.
h.Pay more attention to the temperature and humidity control in the room to avoid condensation and rust caused by improper humidity.
i.When equipment is repaired, dust particles are easily generated, so it is best to carry out maintenance outside the clean room and add isolation fences.
j.For Manufacturers who are engaged in construction or maintenance, the various regulations for entering and leaving the clean room should be informed, and the responsible engineer should be on duty to supervise.
k.There should be a special tool set for the clean room, but it must not be taken out of the clean room for use.
