Occupational health evaluation qualification on-site assessment examination test bank (3)

Second, adhere to the social benefit first, strengthen social responsibility, vigorously publicize the national guidelines and policies on prevention and treatment of occupational diseases, and protect the health rights and interests of workers.

Third, adhere to the principle of honesty and trustworthiness, in accordance with the law to carry out occupational health technical services, to ensure that the technical conclusions are scientific, objective, true, and bear legal responsibility for the issuance of occupational health technical reports.

Fourth, adhere to the concept of quality service, strengthen the sense of service, strengthen self-construction, and constantly improve the capacity and level of occupational health technical services.

Fifth, adhere to the market rules of fair competition, due diligence, consciously maintain the image and reputation of the industry.

Six, adhere to the integrity of the profession, abide by professional ethics, the obligation of confidentiality, consciously resist improper practice.

18. noise measurement of the key points?

A: Measurement should be carried out under normal production conditions.

Microphone should generally wear a windshield, wind speed more than 4, should stop measuring (experiments show that the wind speed ?3m / s, wearing a windshield or not on the test results have no significant impact, the wind speed up to 4, 5m / s, do not wear a windshield than wearing a windshield were higher than the windshield 7.5 and 16dB (C); 0.5 and 3.5dB (A). Therefore, wind speed >3m/s, should wear a windscreen, wind speed more than 5m/s should stop measuring).

The relative temperature of the workplace is more than 90%, moisture microphone should be used.

Away from the electromagnetic field, to avoid interference (can be excluded by adjusting the microphone pointing).

Batteries can not be reversed, should be removed after use.

To load or unload the condenser microphone, the battery must be turned off.

The instrument should be calibrated periodically.

Measurements should be made after the registration of the use of the equipment.

General production noise measurements should be measured in the workplace noise intensity greater than 80dB (A), less than 78dB (A) is not as noise operations.

19. What are the main contents of the site investigation before sampling?

(1) the work process using raw materials, auxiliary materials, production of products, by-products and intermediate products, such as the type, quantity, purity, impurities and their physical and chemical properties.

(2) The workflow includes the way of raw material input, production process, heating temperature and time, production methods and the degree of integrity of production equipment.

(3) The working condition of the workers, including the number of workers, the duration of stay at the workplace, the way of work, the degree, frequency and duration of exposure to hazardous substances, and so on.

(4) The generation and diffusion pattern, existence status, and estimated concentration of hazardous substances in the air at the workplace.

(5) The hygiene and environmental conditions of the workplace, health protection facilities and their use, and personal protection facilities and their use.

20. Combined with the actual work, talk about your unit is how to carry out laboratory quality control?

Laboratory quality control has the following practices:

(1) Determination of the standard deviation of the blank within the batch, the calculation of the detection limit of the assay method is stable;

(2) Sample spiking recoveries: through the determination of spiked samples of the recovery, in order to find the existence of the experimental process does not affect the precision, but can change the method of the accuracy of the factors;

(3) Precision experiment of the standard: by comparing the intra-batch variation and inter-batch variation of each concentration of the standard (gas or solution, excluding the blank), to check the error brought about by the standard preparation operation and experimental conditions;

(4) Elution and Desorption Efficiency: through the experiment of elution and desorption efficiency of the high, medium, and low concentrations, to check out the error during the sample processing;

(5) Use of the standard substance : Check the reliability of the standard (gas or solution) prepared in this laboratory, by testing the quality control samples or assessment standards uniformly distributed by the laboratory of the previous level, compared with the standard prepared in this laboratory;

(6) Establishment of control charts: control charts are used to constantly check the precision and accuracy of the test method, so that changes due to time can be corrected at any time;

(7) Quality control Detection and evaluation of blank samples.

Third, calculation questions

1. A workshop of a type of work 5 days a week, the daily working time of 8h. According to the investigation of the work of laborers exposed to ethyl acetate (PC-TWA for 200mg/m3) conditions are: 300 mg/m3, exposure to 3 hours; 60 mg/m3, exposure to 2 hours; 120 mg /m3 for 3 hours. Based on the above, please analyze and determine whether the level of exposure to ethyl acetate for workers in this job meets the hygienic requirements, and ask for justification.

Answer: (1) The concentration of ethyl acetate per work shift is:

CTWA=(C1T1+C2T2+C3T3)/8=(300?3+60?2+120?3)?8=172.5(mg/m3)

Smaller than PC-TWA(200mg/m3). Therefore, the level of exposure to ethyl acetate does not exceed the National Occupational Exposure Limit (NOEL) and meets the requirements.

2. a workshop using diluent, hourly consumption of 3kg. diluent of the main components: xylene 30%, 50% ethyl acetate, ethanol 20%, calculate the minimum air volume required to meet the health standards of the workshop air.

No. Chinese name occupational exposure limit (mg/m3)

MACPC-TWAPC-STEL

1. xylene-50100

2. ethyl acetate-200300

3. ethanol-

Answer: According to the formula L=M/YS-Y0;

Where ∶ L-exchange rate is 20%. p> where ∶ L - air exchange volume, m3 / h;

M - the amount of hazardous substances generated. Mg / h;

YS - health standards in the occupational exposure limits; mg / m3;

Y0 - fresh air in the background concentration of the hazardous substances, mg / m3.

Xylene consumption M is ∶ 3?1000?1000? 30%=900000mg;

Ethyl acetate consumption M is: 3?1000?1000?1000?50%=1500000mg;

According to the actual production, the occupational exposure limit value selected PC-TWA value, that is, YS (xylenol) for 50mg/m3, YS (ethyl acetate) for 200mg/m3, Y0?0

L=900000/50%=900000/m3, Y0? p> L=900000/50-0+1500000/200-0=18000+7500=25500m3/h=25500/3600

=7.08 m3/s

Therefore, the workshop air meets the health standards of the minimum air volume of 7.08 m3/s.

3. A local exhaust system as follows As shown in the figure, the structure of the three local exhaust hoods is exactly the same.

It is known that the total system air volume L = 2m3 / s, point A static pressure PAj = -100Pa; point B static pressure PBj = -150Pa; point C static pressure PCj = -100Pa. find the exhaust hood of the air volume.

Answer: According to the formula Q= ;

Where: Q-exhaust hood of the exhaust volume, m3 / h;

F- hood mouth connecting tube measured cross-section of the area, m2;

F- hood mouth connecting tube measured cross-section. Area, m2;

Pj ? Measured section of the static pressure, Pa;

? -density of the gas in the tube, kg/m3;

u-flow coefficient, only related to the structural shape of the exhaust hood.

According to the known conditions, FA = FB = FC;

get: QA + QB + QC = 2

QA = QC

Therefore: QA = QC = 0.62m3/h;

QB = 0.76m3/h.

Four. >

1. A silicate cement plant to carry out pre-evaluation of occupational hazards, as an evaluator, in the pre-evaluation of occupational hazards in the preparatory stage of the work should be completed what work? And describe the main production process links of the silicate cement plant and the identification of the main occupational hazards of each link.