RU2511022C2 - Method of multi-criteria assessment of comfort of working area in production premises - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building, in particular, to devices of safety systems. The method of multi-criteria assessment of comfort of a working area in production premises consists in determination of concentration of air-dispersed admixtures and parameters of microclimate of air volume, first they determine working area air dustiness as the first criterion of its comfort. For this purpose they prepare and tune equipment for determination of pure filter mass, then the pure filter is weighed on a scale. After this they tune a plant for forced deposition of a dust aerosol in the working area of the production room. Then air is sampled with capture of dust particles on the filter, the filter is weighed with caught particles of dust, the concentration of the dust aerosol is calculated in mg per cubic metre. Afterwards they assess dustiness of working area air, comparing the obtained concentration with the permissible value. Further they measure air temperature using a thermograph or psychrometer, air moisture using a stationary or an aspiration psychrometer, and they determine speed of air movement using a cup or a windmill anemometer. On the basis of the produced parameters - air temperature in the working area, its moisture and speed of movement, they calculate extent of comfort, afterwards they assess comfort of microclimate parameters according to the following scale: 1 - very hot; 2 - too hot; 3 - warm, but nice; 4 - feeling of comfort; 5 - cool, but nice; 6 - cold; 7 - very cold. Then they select an indicator powder from the entire set of sorbents, available gas analysers with account of statistic data of this or that production type, then appropriate indicator tubes are prepared for each detected air admixture, filling them with the appropriate indicator powder, and a sample is taken with the help of a gas analyser. At the same time a certain volume of air passes via an indicator tube for a certain period of time, afterwards they analyse the taken sample, for this purpose they apply an indicator tube to a standard scale available within a set of this or that type of a gas analyser, and by the length of the indicator powder that changed its colour they determine concentration of the harmful substance in the inspected air. Then actual concentration of hazardous substance produced as a result of the experiment, is compared with the maximum permissible concentration (MPC) by norms, and the comparable assessment table is filled in, then, using the tables, they detect substances with effect of summation, and perform calculations according to the following formula: $$\frac{C_1}{MP{C}_1}+\frac{C_2}{MP{C}_2}+\cdots +\frac{C_n}{MP{C}_n}\le \mathrm{1,}$$

where C₁, C₂, … C_n - actual concentrations of substances in atmospheric air, mg/m³; MPC₁, MPC₂, … MPC_n - maximum permissible concentrations of the same substances, mg/m³. Then with account of the fact that whenever several substances with summation of action are jointly present in atmospheric air, the sum of their concentrations should not exceed one, the conclusion is made on compliance with norms of each of the specified substances separately and with their simultaneous action.

EFFECT: higher efficiency, effectiveness and reliability of system actuation.

7 dwg, 1 tbl

Description

The invention relates to mechanical engineering, in particular to devices of security systems.

The closest object in technical essence to the claimed is a method for studying the comfort of the environment of industrial premises by dust factor by determining the concentration of dust by the weight method according to RF patent No. 2422802 - prototype.

A disadvantage of the known solution is the relatively incomplete picture of the comfort of the working area due to the lack of information about the parameters of its microclimate, such as temperature, humidity and air velocity.

The technical result is an increase in the efficiency of determining the comfort of the working area of industrial premises.

This is achieved by the fact that in the method of multi-criteria assessment of the comfort of the working area of industrial premises, which consists in determining the concentration of aerodispersed impurities and the microclimate parameters of the air volume, the dust content of the working area air is first determined as the first criterion for its comfort, for which the equipment for determining the mass of the clean filter is prepared and tuned , then a clean filter is weighed on the balance, and then the unit is set up for forced deposition of dust aerosol in the working zone e industrial premises, then produce air sampling with capture dust particles on the filter and weighed filter with the collected particles of dust, dust aerosol concentration is calculated in milligrams per cubic meter according to the formula:

C = (m ₂ −m ₁ ) / V _o ,

where m ₂ is the mass of dusty filter, mg; m ₁ - mass of pure filter, mg;

V _o is the volume of air (m ³ ) passed through the filter.

Figure 1 shows a schematic diagram of an installation for sampling air, figure 2 is a filter for sampling air, figure 3 shows a General view of a stationary psychrometer, figure 4 is a General view of a digital anemometer, figure 5 shows a diagram installation for determining the concentration of hazardous substances in the air, Fig.6 is a diagram of a universal portable gas analyzer, Fig.7 is a scale diagram for determining the concentration of toxic impurities in the air, for example for carbon monoxide.

Installation for sampling air (Fig. 1) contains a clamping nut 1, an AFA filter (Fig. 2), a filter holder (allonge) 3, a flowmeter 4, an adjustment valve 5, a tee 6, an aspirator 7.

The sampling rate is set taking into account the degree of dustiness of the air and the technical capabilities of the aspirator, but not higher than 100 l / min. At speeds of 30-100 l / min in the allonge, a support mesh is installed behind the filter, which prevents the filter from breaking. At the end of the sampling, the aspirator and stopwatch are turned off.

Installation for determining the parameters of the microclimate of the working area (figure 3 and 4) includes a hygrometer-psychrometer VIT-2. The measurement of relative humidity is based on the difference between the readings of the “dry” and “wet” thermometers. After taking the thermometers, the relative humidity is determined from the psychrometric table. Airflow velocity measurement is based on the use of the ATE-1034 anemometer: airflow velocity measurement: 0.2 ... 25.0 m / s; resolution: 0.01 m / s (0.2 ... 5 m / s), 0.1 m / s (5.1 ... 25 m / s); air flow temperature measurement: range: 0 ... 50 ° С.

The installation diagram for determining the concentration of harmful substances in the air is shown in Fig.5. A glass bottle 2 with vapors of the corresponding harmful substance (ammonia, acetone, etc.) is used as a simulator of the production room air, and a universal gas analyzer 1, which is connected by a rubber tube 6 to an indicator glass tube 5, is used as a device for detecting their presence. Determination of concentration harmful substances in the air using a gas analyzer is a linearly coloristic method based on the use of indicator tubes. The indicator powders attached to the device (not shown in the drawing) in glass ampoules make it possible to determine the air content of ammonia, acetone, carbon monoxide, hydrogen sulfide, ethyl ether, nitrogen oxides, chlorine, gasoline, benzene, xylene, toluene, hydrocarbons. For each determined air impurity, appropriate indicator tubes should be prepared by filling them with the corresponding indicator powder, which is held in them with cotton swabs on both sides (not shown in the drawing).

The glass bottle 2 is equipped with a rubber tube 3 having a clip 4. Between the rubber tubes 3 and 6 of the glass bottle 2 and the gas analyzer 1, an indicator tube 5 is installed into which the corresponding indicator powder is filled. When air containing toxic impurities is drawn from a glass cylinder 2 using a gas analyzer 1 in the indicator tube 5, a reaction occurs between the detected harmful substance and the indicator powder reagent, which changes color to a certain length of the tube. The length of the colored powder layer is proportional to the amount of harmful substance in the air drawn through the indicator tube.

A universal gas analyzer consists of a housing 19 (Fig. 6) of an air intake device in which a corrugated rubber bellows 18 with two flanges and a cup with a spring 17 are located. Spacer rings 16 are installed in the inner bellows corrugations to give it rigidity and maintain a constant volume. On the upper plate 11 of the housing there is a stationary sleeve 13 for guiding the rod 14 during compression of the bellows. A rubber tube 8 is put on the fitting 9 from the inside, which is connected through the lower flange to the internal cavity of the bellows. A glass tube filled with indicator powder is attached to the free end of the rubber tube 10 during analysis. The test air is sucked through the indicator tube after preliminary compression of the bellows rod. On the faces (under the head) of the rod, the volumes of air sucked during analysis are indicated.

Four longitudinal grooves are made on the cylindrical surface of the stem with two grooves 15, designed to fix the two positions of the stem with a stopper 12. The distance between the grooves on the grooves is selected so that when the stem moves from one groove to the other, the bellows takes a predetermined volume of the studied air.

The length of the colored column of the indicator powder in the tube is proportional to the content of the measured substance in the test air. It is determined by specially calibrated scales (Fig. 7) for each of the two volumes of extended air. Each scale indicates the length of the colored column of the indicator powder corresponds to this concentration. The time of the experiment depends on the volume of sucked air (stroke). It is measured by a stopwatch. The control suction time is also indicated on the scales. For a more accurate determination of the actual concentration of harmful gas or vapor in the air of the working area, at least three experiments are carried out, starting with measurements of a smaller volume from those indicated on the scales. If the indicator powder is not colored or the length of its colored part is very small, then proceed to the study of a larger volume of air.

A method for assessing the comfort of the working area by the criterion of dust is as follows.

Throughout the entire sampling time, the aspirator control valve maintains a constant air volumetric flow rate. The duration of sampling is selected depending on the dust content and flow rate. The minimum required dust sample on the filter should be at least 1 mg, and the maximum allowable - not more than 100 mg. At the end of sampling, all used (dust-contaminated) filters are weighed on the same balance.

The calculation of the aerosol concentration is as follows.

The air volume (m ³ ) passing through the filter is first brought to normal conditions (i.e., to the volume that it would occupy at a temperature of 0 ° C and normal atmospheric pressure equal to 101325 Pa) according to the formula

$$V_o=\frac{273}{273+T}\frac{B_F}{{\mathrm{AT}}_N}\frac{\upsilon \tau }{1000}\left(\text{one}\right)$$

where 273 is the absolute temperature, K;

T - air (gas) temperature, ° С; In _f - the actual barometric pressure at the time of sampling, Pa; In _n - normal atmospheric pressure equal to 101325 Pa; ν is the sampling rate, l / min; τ is the sampling time, min; 1000 - coefficient of conversion of liters to cubic meters (1 m ³ = 1000 l).

The aerosol concentration (mg / m ³ ) is determined by the formula

$$C=\left(m_2-m_{\mathrm{one}}\right)/V_o,\left(\text{2}\right)$$

where m ₂ is the mass of dusty filter, mg; m ₁ - mass of pure filter, mg.

Then assess the dustiness of the air of the working area, comparing the obtained concentration with an acceptable value.

The way to assess the comfort of the working area according to the criterion of microclimate parameters is as follows.

Be sure to observe the following order of operations when determining microclimate parameters:

1. Determine the air temperature using a thermometer (figure 3).

2. Determine the relative humidity using an aspiration psychrometer. For what it is necessary: with a pipette, moisten with water a piece of batista fixed on the reservoir of a wet thermometer; use a key to start the gas spring of the device, which drives the fan impeller; after 4 minutes, take readings on dry and wet thermometers; calculate the psychrometric difference Δt = t _c -t _m ; from the calculated psychrometric difference Δt using a psychrometric table to determine the value of relative humidity. Record the results of measurements and calculations in the protocol.

3. To determine the speed of air movement using a vane anemometer (figure 4).

Based on the obtained parameters - air temperature in the working area, its humidity and speed - calculate the degree of comfort using the following formula:

S = 7.83-0.1t _B -0.0968t _O -0.0372P + 0.18ν (37.8-t _B ),

where t _B - air temperature in the working area of the production room; t _O is the temperature of the surrounding surfaces in the working area; ν - air velocity, m / s; P is the partial pressure of water vapor, calculated by the formula:

P = 0.01φ × Rnas, mmHg,

where φ is the relative humidity,%; Rnas - partial pressure of water vapor in a saturated state, determined by the reading of a dry thermometer from table 1:

Then assess the comfort of the microclimate parameters on the following scale: 1 - very hot; 2 - too warm; 3 - warm, but nice; 4 - a sense of comfort; 5 - cool, but nice; 6 - cold; 7 - very cold.

An example of the proposed method

one). To build the dependence of the air velocity on the comfort indicator if the thermometer readings on the psychrometer in the weaving mill of the factory were: dry t _C = 24 ° C, wet t _M = 19.5 ° C. Category of work - IIb, comfort indicator S = 4. Take the temperature of surrounding objects equal to the air temperature in the workshop, i.e. t _o = t _B , which in turn is determined by the readings of a dry thermometer, i.e. t _B = t _C.

2). To draw a conclusion, comparing the results obtained with acceptable norms of the microclimate parameters for the warm season with a slight excess of apparent heat according to GOST 12.1.005-88, and, if the results do not match the normative values, calculate the comfort index S for the upper range of acceptable values of those microclimate parameters that do not match valid values.

The difference in the readings of dry and wet thermometers is usually called the psychrometric difference (Δt = t _c -t _m ); it serves to determine humidity, φ,%.

In our case, Δt = t _c -t _m = 24-19.5 = 4.5 ° C. Therefore, the relative humidity in the workshop will be φ = 65%. So for the calculation, the following data were obtained:

t _B = 24 ° C; φ = 65%.

Now we calculate the partial pressure of water vapor according to the formula

P = 0.01φ × Rnas, mmHg, where Rnas is the partial pressure of water vapor in a saturated state, determined by the reading of a dry thermometer from Table 1.

Table 1 The dependence of the partial pressure of water vapor in a saturated state on air temperature Air temperature t _B , ° С The partial pressure of water vapor, Rnas,
mmHg. Air temperature t _B , ° С The partial pressure of water vapor, Rnas, mm Hg 10 9,209 21 18,650 eleven 9,844 22 19,827 12 10,518 23 21,068 13 11,231 24 22,377 fourteen 11,987 25 23,756 fifteen 12,788 26 25,209 16 13,634 27 26,739 17 14,530 28 28,349 eighteen 15,477 29th 30,043 19 16,477 thirty 31,824 twenty 17,533 31 33,695

For our temperature value t _B = 24 ° С, the partial pressure of water vapor in the saturated state is Рнас = 22.38.

Then the partial pressure of water vapor for our case is determined as follows:

P = 0.01φ × Pnas = 0.01 × 65 × 22.38 = 14.5 mmHg

Now we determine the required speed of air movement in the weaving shop, at which the index of well-being would be equal to S = 4:

$$\nu =\frac{S+0.1t_B+0.0968t_O+\mathrm{0,0372}P-7.83}{0.18\left(37.8-t_B\right)}=\frac{\mathrm{four}+0.1\times 24+0.0968\times 24+\mathrm{0,0372}\times 14.5-7.83}{0.18\left(378-24\right)}=0.58m/\mathrm{from}$$

The health indicator can have the following values: 1 - very hot; 2 - too warm; 3 - warm, but nice; 4 - a sense of comfort; 5 - cool, but nice; 6 - cold; 7 - very cold.

The S indicator can also be expressed in a fractional number, which allows you to more accurately assess what kind of sensation (for example, 3 points - heat or 4 points - comfort, etc.) are closer to certain states of well-being of a person. For light physical work S = 3; for moderate work S = 4; for heavy physical work S = 5 points.

The given dependence allows us to solve the inverse problem, if necessary. Given the necessary degree of comfort and optimal values of temperature and humidity, you can calculate the necessary speed of air movement, which for these specific conditions will most of all meet the requirements of ensuring comfort.

The method for determining the concentration of harmful substances in the air is as follows.

The corresponding indicator tubes are prepared for each determined air impurity, filling them with the corresponding indicator powder, which is held in them with cotton swabs on both sides. In the sleeve 13 of the gas analyzer, insert the rod 14 corresponding to the flow rate of the drawn air so that the latch 12 slides along the groove of the rod. By pressure of the hand, the bellows 18 is compressed from above onto the rod 14 until the stopper enters the upper recess 15 of the rod groove 14.

Then connect one end of the indicator tube 5 with the rubber tube 6 of the gas analyzer, and the other end with the rubber tube 3 of the glass bottle 2. Then loosen the clamp 4 on the rubber tube of the glass bottle 3, allowing air to flow with the vapors of the harmful substance through the indicator tube 4. Holding with one hand the rod 14, with the other hand they release the clamp 12, allowing the rod 14 to rise under the action of the spring for a period of time specified on the standard scale until the stopper enters the lower recess in the groove current. At the same time, a certain amount of air will pass through the indicator tube for a specified time.

Clamp the clamp 4 on the glass bottle 2 and release the indicator tube 5 from the rubber tubes 3 and 6. Then, the indicator tube 5 is applied to a standard scale 7 and the concentration of the harmful substance in the test air is determined by the length of the color of the indicator powder. Then, the actual concentration of the harmful substance is compared with the maximum permissible concentration (MPC). The indicator powder is selected from the entire set of sorbents available for a certain type of gas analyzer, taking into account the statistical data of one or another type of production. The corresponding indicator tubes are prepared for each determined air impurity, filling them with the corresponding indicator powder, which is held in them with cotton swabs on both sides. A sampling is made, for which a rod 7 is inserted into the sleeve 6 of the gas analyzer according to the flow rate of the drawn air so that the latch 5 slides along the groove of the rod. By pressure of the hand, the bellows 11 is compressed from above onto the rod 7 until the stopper engages in the upper recess 8 of the rod groove 7. Then, one end of the indicator tube is connected to the rubber tube of the gas analyzer, and the other end to the rubber tube of the glass cylinder (not shown in the drawing ) Then the clamp on the rubber tube of the glass bottle is loosened, allowing air to be drawn in with vapors of the harmful substance through the indicator tube. Holding the rod 7 with one hand, the latch 5 is withdrawn with the other hand, allowing the rod 7 to rise under the action of the spring for a period of time specified on the standard scale until the stopper enters the lower recess in the rod groove. At the same time, a certain amount of air will pass through the indicator tube for a specified time. Cover the clip on the glass bottle and release the indicator tube from the rubber tubes.

An analysis of the selected sample is carried out, for this purpose an indicator tube is applied to a standard scale, which is available in the kit of one or another type of gas analyzer, and the concentration of the harmful substance in the test air is determined by the length of the indicator powder that has changed color.

Then, the actual concentration of the harmful substance obtained as a result of the experiment is compared with the maximum permissible concentration (MPC) and the comparative evaluation table No. 1 is filled out.

The content of harmful substances in the atmospheric air of populated areas is standardized according to the list of the Ministry of Health No. 3086-84, and for the air of the working area of industrial premises - according to GOST 12.1.005-88. Then, substances with summation are identified, the necessary calculations are performed according to formula (1), and a conclusion is made on the compliance with the standards of each of these substances separately and with their simultaneous exposure. With the simultaneous presence in the atmospheric air of several substances with the summation of action, the sum of their concentrations should not exceed 1 (unit) when calculated by the formula:

$$\frac{C_{\mathrm{one}}}{PD{\mathrm{TO}}_{\mathrm{one}}}+\frac{C_2}{PD{\mathrm{TO}}_2}+\cdots +\frac{C_n}{PD{\mathrm{TO}}_n}\le \mathrm{one}\left(\text{one}\right)$$

where C ₁ , C ₂ , ... C _n - the actual concentration of substances in atmospheric air, mg / m ³ ;

MPC ₁ , MPC ₂ , ... MPC _n - maximum permissible concentrations of the same substances, mg / m ³ .

Claims (1)

1. A method of multi-criteria assessment of the comfort of the working area of industrial premises, which consists in determining the concentration of aerodispersed impurities and microclimate parameters of the air volume, characterized in that they first determine the dust content of the air of the working area as the first criterion for its comfort, for which they prepare and configure equipment for determining the mass of a clean filter , then a clean filter is weighed on the balance, and then the unit is set up for forced deposition of dust aerosol in the working area oizvodstvennogo premises, then produce air sampling with capture dust particles on the filter and weighed filter with the collected particles of dust, dust aerosol concentration is calculated in milligrams per cubic meter according to the formula:
C = (m ₂ −m ₁ ) / V _o ,
where m ₂ is the mass of dusty filter, mg; m ₁ - mass of pure filter, mg.
V _o - the volume of air (m ³ ) passed through the filter,
the volume of air (m ³ ) passing through the filter must first be brought to normal conditions (i.e., to the volume that it would occupy at a temperature of 0 ° C and normal atmospheric pressure equal to 101325 Pa) according to the formula

where 273 is the absolute temperature, K; T - air (gas) temperature, ° С; In _f - the actual barometric pressure at the time of sampling, Pa; In _n - normal atmospheric pressure equal to 101325 Pa; ν is the sampling rate, l / min; τ is the sampling time, min; 1000 - coefficient of conversion of liters to cubic meters (1 m ³ = 1000 l),
after which the dust content of the working area is evaluated, comparing the obtained concentration with an acceptable value, then the air temperature is measured using a thermograph or psychrometer, then the air humidity is measured using stationary or aspiration psychrometers, and air velocity is determined by cup or vane anemometers based on the obtained parameters - air temperature in the working area, its humidity and speed, calculate the degree of comfort according to the following formula:
S = 7.83-0.1t _B -0.0968t _O -0.0372P + 0.18ν (37.8-t _B ),
where t _B - air temperature in the working area of the production room; t _O is the temperature of the surrounding surfaces in the working area; v is the air velocity, m / s;
P is the partial pressure of water vapor, calculated by the formula:
P = 0.01φ × Rnas, mmHg,
where φ is the relative humidity,%; Rnas - partial pressure of water vapor in a saturated state, after which they evaluate the comfort of the microclimate parameters on the following scale:
1 - very hot; 2 - too warm; 3 - warm, but nice; 4 - a sense of comfort; 5 - cool, but nice; 6 - cold; 7 - very cold, characterized in that the indicator powder is selected from the entire set of sorbents available for the gas analyzer taking into account the statistics of one or another type of production, then the corresponding indicator tubes are prepared for each determined air impurity, filling them with the corresponding indicator powder, and produced sampling using a gas analyzer, while a certain amount of air will pass through the indicator tube for a certain time, after which the analysis is carried out of an early sample, for this, an indicator tube is applied to the standard scale that is available in the kit of one or another type of gas analyzer and the concentration of the harmful substance in the test air is determined by the length of the color of the indicator powder, then the actual concentration of the harmful substance obtained as a result of the experiment is compared with the maximum permissible concentration (MPC) according to the norms and fill out the comparative evaluation table, then the substances with the effect of summation are identified from the tables, and calculations are performed according to the formula

where C ₁ , C ₂ , ... C _n - the actual concentration of substances in atmospheric air, mg / m ³ ;
MPC ₁ , MPC ₂ , ... MPC _n - maximum permissible concentrations of the same substances, mg / m ³ , then taking into account the fact that when several substances with the summation of action are combined in the atmospheric air, the sum of their concentrations should not exceed unity conclusion on compliance with the standards of each of these substances individually and with their simultaneous exposure.

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