This standard specifies the maximum permissible concentration and time-weighted average permissible concentration of petroleum asphalt (fumes) in the air of a workplace and its monitoring and inspection methods. This standard is applicable to all types of industrial enterprises that produce and use petroleum asphalt. GB 18553-2001 Occupational exposure limits for petroleum asphalt (fumes) in the air of a workplace GB18553-2001 Standard download decompression password: www.bzxz.net

GB18553—2001
This standard is formulated for the first time based on toxicological experiments, on-site labor hygiene surveys and occupational population surveys and with reference to foreign occupational exposure limit data. It is a hygienic standard used for workplace environmental monitoring and health supervision. This standard will be implemented from May 1, 2002. Appendix A of this standard is the appendix of the standard.
This standard was proposed by the Ministry of Health of the People's Republic of China. The drafting unit of this standard is: Heilongjiang Provincial Institute of Labor Hygiene and Occupational Diseases. The main drafters of this standard are: Ci Jieyuan, Yang Yinsen, Wang Yunli, Zhang Hongying. This standard is entrusted to the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine for interpretation. 702
1 Scope
National Standard of the People's Republic of China
Occupational exposure limit for petroleum asphalt (fume) in the air nf workplace
GB 18553—2001
This standard specifies the maximum permissible concentration and time-weighted average permissible concentration of petroleum asphalt (fume) in the air of the workplace and its monitoring and inspection methods.
This standard is applicable to the hygienic requirements of various industrial enterprises producing and using petroleum asphalt.
The maximum permissible concentration of petroleum asphalt (fume) in the air of the workplace is 8mg/m2; the time-weighted average permissible concentration is 5mg/m2. 3 Inspection method
The inspection method of this standard adopts ultraviolet spectrophotometry, see Appendix A (Appendix to the standard). Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on December 4, 2001 -rrKAoNrKAca-
Implementation on May 1, 2002
A1 Principle
GB 18553-2001
Appendix A
(Appendix to the standard)
Ultraviolet spectrophotometry
Use silicone tube to collect air asphalt, and desorb it by cyclohexane. The desorbed asphalt has a characteristic absorption peak in the wavelength range of 200 nm to 300 nm. The asphalt liquid content is determined based on the linear relationship between concentration and absorbance. A2 Instruments
A2.1 Silica gel sampling tube: Solvent desorption type, use a glass tube with a length of 80 mm and an inner diameter of 3.5 mm~～4.0 mm, with 20 mg in the front section and 50 mg in the back section of 40-~60-day silica gel, plug the two ends and the middle of the glass tube with absorbent cotton, and cover the two ends with plastic: A2.2 Empty sampler: flow rate 0 I./min～1 L./min. A2.3 Stoppered test tube: 10ml.
A2.4 UV spectrophotometer, 10mm quartz cup. A3 Reagents
A3.1 Cyclohexane, no interference with the absorption peak of the measurement. A3.2 Fuel stock solution: Take an appropriate amount of asphalt that is the same as the sample to be excited and put it in a 250ml chain bottle. Slowly heat the conical bottle to produce asphalt and volatiles. Use a vacuum pump to draw out at a flow rate of 0.2L/min. Let it be absorbed in two large bubble absorption tubes in series containing 10mL cyclohexane, until the cyclohexane turns yellow, pour it into a constant weight evaporator, heat it in a water bath to completely volatilize the cyclohexane, and bake it in an 80C oven to constant weight. The difference between the two weights is the weight of the asphalt smoke. Dissolve the residue in the evaporator with cyclohexane, transfer it quantitatively to a 100mL volumetric flask, dilute to the scale, shake, and calculate the concentration of asphalt smoke per milliliter of solution. Store in a refrigerator for later use. A3.3 Blue smoke standard solution: Pipette an appropriate amount of stock solution into a 100mL volumetric flask, dilute to the scale with cyclohexane, and shake. Prepare an asphalt smoke solution containing 10 per liter.
A4 Sampling
Open both ends of the silica gel sample tube at the sampling site and sample for 20min~30min at a flow rate of 0.51./min~1.0L/min. After sampling, seal both ends and bring back to the laboratory for analysis. A5 Analysis steps
A5.1 For the test: Bring the silica gel sampling tube to the site. Except for not collecting air, the rest of the operations are the same as the sample, which serves as a blank control for the sample. A5.2 Sample treatment: Pour the front and back two sections of silica gel and absorbent cotton into the stoppered test tubes, such as 10 mL of asphalt, mix, stopper and place at room temperature for 81
A5.3 Drawing of standard curve: In seven 10 ml test tubes, prepare the standard series according to Table A1. Table AI
Standard solution.ml.
Cyclohexane, ml,
Asphalt smoke content·
Select the most significant absorption peak at a wavelength of 200nm~300nm (depending on the type of blue smoke). Determine the absorbance and draw a standard curve based on the blue smoke content and absorbance.
GB 18553—2001
A5.4Sample analysis: At the same wavelength as the standard series, measure the absorbance of the sample desorption solution, and obtain the asphalt smoke content from the standard curve.
A6Calculation
A6.1Convert the sample volume into the volume under standard conditions according to formula (A1). V. =V, ×
Where: V. — converted or standard sampling volume, L. V, — sampling volume at C: and, L
— steam temperature at the sampling location, ℃.
- temperature at the sampling location, kpa.
A6.2Calculate the concentration of petroleum asphalt smoke in the air according to formula (A2). Where t
the concentration of petroleum asphalt smoke in the air, mg/m
respectively are the asphalt smoke content in the desorption solution of the silica gel sample tube before the start, V. ——Converted into the sampling volume under standard conditions.L. A7 Description
A7.1 The detection limit of this method is 0.5μg/mL, and the minimum detection concentration is 0.5mg/m (sampling 10L air*). (A
47.2 The silicone tube collects petroleum asphalt smoke in the air. When the concentration is 21.5mg/m2, its adsorption capacity is 0.202mg/200mg silica gel. The desorption efficiency of cyclohexane on the sample is 96.2%~103.4%, and the average is 100%. A7.3 When preparing asphalt smoke stock solution, the heating temperature of the conical flask should be close to the on-site operating temperature, otherwise the composition of the standard and the sample will be too different, affecting the measurement results.www.bzxz.net
A7.4 The purity of cyclohexane is required to be above 99.0%, and there should be no absorption peak within the measurement wavelength range. TTKAON KAca-
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