Sanitary classification of enterprises and production facilities

№	Class	Size of SPZ, m
1	First	1000
2	Second	500
3	Third	300
4	Forth	100
5	Fifth	50

The size of SPZ should be specified separately for different wind directions, depending on the results of the calculation of air pollution by the mentioned methods (ОНД-86[2.11]) and the average annual previously wind rose of the area of the enterprise location:

(3.20)

where: L is the calculated size of SPZ, m; L₀ is the established distance from the emission source to the border of SPZ, without correction for the annual wind rose, m; P is the averaged frequency of wind directions for considered rhumb,%; P₀ is the frequency of wind directions of one rhumb,% (P₀=12.5%);

The residential construction, including individual houses, landscape and recreation areas, sanatoriums, collective or individual cottages, as well as other areas with regulated quality of habitat are not allowed to be located within the boundaries of SPZ.

Production facility or enterprises to serve the employees of such an object (non-residential premises for the alert emergency personnel, administrative buildings, research laboratories, clinics, sports and recreation facilities of closed type, motels, hotels, garages, playgrounds and facilities for storage of public and private transport , fire stations) are allowed to be placed within the boundaries of SPZ.

The normative size of SPZ should be specified by calculation and measurement methods taking into account actual air pollution and enterprise development perspective. In cases when the normative size of SPZ of the enterprise is not supported by calculation results according to methods (ОНД-86), the decision concerning the change of production technology should be considered to reduce harmful emissions into the atmosphere or otherwise conversion, or closure of the industrial object.

Example: define the maximum permissible emission sulphur dioxide and size of sanitary protection zone for a boiler plant of thermal power station taking into account the perspective of enterprise development and the average annual wind rose of the area of the industrial object location (input data in Table C.2).

The value of MPE of SO₂ for the boiler plant of the thermal power station is calculated by the formula (3.19) and some coefficients have been already estimated in the previous task (problem 3.2):

g/s

The size of SPZ for the boiler plant of the thermal power station is determined by the formula (3.20) taking into account the average annual wind rose of the area of the enterprise location (Fig.3.5, Table C.2).

In accordance with the sanitary classification of enterprises [3.1], the normative size of SPZ, L₀=300 m (III class).

So, for north wind direction: m.

Calculation results for other wind directions are collected in Table 3.3.

Table 3.3

Size of sanitary protection zone for a boiler plant of a thermal power station

Wind direction	N	NE	E	SE	s	ws	w	nw
Wind directions frequency, %	14	11	12	13	13	11	17	14
Size of SPZ, m	336	264	288	312	312	264	408	336

Conclusion: the real efficiency of SO₂ emission is 2.6 times less than the estimated value of normative MPE. So, exploitation of the boiler plant of the thermal station does not deteriorate air quality of the adjacent habitation area. SPZ for the boiler plant of the thermal power station has been estimated by considering the average annual wind rose in separate enterprise zones from habitation area and in human safety conditions.

Fig.3.5. Annual wind rose of the area of thermal power station

Fig.3.6. Size of sanitary protection zone for different wind direction

Key questions and tasks:

1. Give a definition of hazardous production facility.

2. How do you understand “harmful substance”?

3. What types of harmful substances do you know?

4. What characteristics does toxicity of substance depend?

5. Give a definition of lethal dose.

6. What basic source of air contamination do you know?

7. Define the most crucial air contaminants on global and local scales.

8. Describe adverse impact PM, NOx on human health.

9. Give a definition of maximum permissible concentration.

10. What criteria are used in Ukraine for air quality regulation?

11. What methods do you know for determinating concentration of harmful substances, gases and dust?

12. Give a definition of ventilation.

13. What types of ventilation do you know?

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