3.5　Noises

3.5.1　Effective measures shall be taken for the main noise sources to control the noise to minimum levels.On the premise of meeting safety and process flow，provisions should be made for noise reduction such as noise absorption，noise elimination and vibration damping.Acoustic enclosures should not be used.When sound insulation hoods are used，ventilation devices shall be provided，and the design of ventilation devices shall be facilitate unit maintenance.

3.5.2　The overall noise level（A-weighted sound pressure level）measured at 1m from the unit shall not exceed the limit values shown in Table 3.5.2.

Table 3.5.2　Health Limits for Noise Levels in Workplaces

Note:the data in this table is calculated by using the formula in the current industrial standard GB/T 189.8 Measurement of Physical Agents in Workplace-Part 8：Noise and in accordance with the current national standard GBZ 2.2 Occupational Exposure Limits for Hazardous Agents in Workplace-Part2：Physical Agents，Article 11.2.