HJ 733-2014 PDF in English
HJ 733-2014 (HJ733-2014) PDF English
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Guideline for the Determination of Volatile Organic Compound Leaks and Uncovered Liquid Surface Emissions
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Standards related to (historical): HJ 733-2014
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HJ 733-2014: PDF in English HJ 733-2014
HJ
NATIONAL ENVIRONMENTAL PROTECTION STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Guideline for the determination of volatile organic
compound leaks and uncovered liquid surface emissions
ISSUED ON: DECEMBER 31, 2014
IMPLEMENTED ON: FEBRUARY 01, 2015
Issued by: Ministry of Environmental Protection
Table of Contents
Foreword ... 4
1 Scope of application ... 5
2 Terms and definitions ... 5
3 Instruments and equipment ... 7
4 Testing technical requirements ... 9
5 Safety protection requirements ... 13
6 Quality assurance and quality control ... 13
Guideline for the determination of volatile organic
compound leaks and uncovered liquid surface emissions
1 Scope of application
This Standard specifies the technical requirements for the detection of volatile organic
compounds (VOCs) originating from equipment leaks and uncovered liquid surface
emissions. It specifies the detection methods, instrument and equipment requirements,
quality assurance and control of VOCs from unorganized emission sources such as
equipment leaks and uncovered liquid surface. This Guideline is not applicable to the
direct determination of mass emission rates of VOCs from leakage and uncovered liquid
surface emission sources.
2 Terms and definitions
2.1 leak sources
Various equipment and pipelines that contain VOCs materials and may leak and emit,
including valves, flanges and other connections, pumps, compressors, pressure relief
devices, open-ended valves or open pipelines, sampling connection systems, exhaust
ports of pump and compressor sealing systems, tank breathing ports, inspection port
seals, etc.
2.2 open-ended valve
Valves in which one side of the valve seat is in contact with organic gas or volatile
organic liquid and the other side is in contact with the atmosphere, but a pressure relief
device is not included.
2.3 uncovered liquid surface
The unorganized emission source from the uncovered liquid surface of the collection,
transportation and storage equipment of production materials containing VOCs and the
uncovered liquid surface of the production process wastewater and waste liquid
collection and storage and purification treatment equipment.
2.4 leak definition concentration
The concentration limit specified in relevant emission standards or regulations,
measured on the surface of the leakage source or the uncovered liquid surface,
indicating the existence of VOCs leakage and requiring measures to be controlled
(based on the measurement reading of an instrument calibrated with a reference
compound).
2.5 no detectable emission
When the concentration of VOCs measured on the surface of the source to be measured,
after subtracting the background, is lower than 2.5% of the standard concentration limit,
it is defined as no detectable emission.
2.6 reference compound
The reference compounds in this Guideline refer to the VOCs compounds specified in
relevant emission standards or regulations and used as the calibration benchmark for
leakage measurement instruments. For example, if an emission source in a certain
emission standard uses methane as the reference compound, the standard concentration
limit is 500×10-6 mol/mol.
2.7 calibration gas
It refers to VOCs compounds used during calibration to adjust instrument readings to
known concentrations. The calibration gas is usually a reference compound standard
gas close to the concentration limits of the relevant control standard.
2.8 response factor
It refers to the ratio of the concentration value of a known concentration of VOCs
compounds to the instrument reading calibrated with a reference compound of the same
concentration value.
2.9 response time
It refers to the time it takes for the instrument to measure the concentration of VOCs
from when the instrument reading begins to change to when the instrument finally
displays 90% concentration of a stable reading.
2.10 zero gas
It refers to clean air with VOCs content less than 10×10-6 mol/mol (calculated as
methane).
2.11 reference compound standard gas
It refers to the reference compound standard gas whose balance gas is high-purity air,
whose concentration is near the relevant control standard concentration limit, and
whose relative expanded uncertainty is 2% (k=2).
2.12 non-reference compound gas
It refers to compound standard gases other than reference compounds. It is used to
determine the response ratio of non-reference compounds and reference compounds on
the detection instrument. When measuring the non-reference compound gas sample, the
measured ratio can be used to convert the instrument response value into the actual
concentration value of the non-reference compound.
3 Instruments and equipment
3.1 Portable testing equipment
3.1.1 Before use, check or experiment shall be carried out to ensure that the detector
responds to the main VOCs components emitted by the emission source to be measured.
Instrument detector types include flame ionization detectors, photoionization detectors,
infrared absorption detectors, etc., and can also be other types of detectors.
3.1.2 The measuring range of the instrument shall be able to meet the measurement
requirements of the standard concentration limits in the relevant control standards. Its
resolution shall ensure readability within ±2.5% of the leak definition concentration or
standard concentration limit in the emission standard.
3.1.3 Be equipped with an electric sampling pump that can provide continuous flow.
The sampling flow rate measured at the top of the sampling probe with a glass wool
plug or filter installed to protect the instrument shall be in the range of 0.10~3.0 L/min.
3.1.4 Be equipped with a sampling probe. The outer diameter of the front end of the
sampling probe shall ensure that it can enter the narrow gaps of various types of
equipment for detection. It generally does not exceed 7 mm.
3.1.5 The instrument must be explosion-proof safe and pass explosion-proof safety
inspection certification.
3.2 Instrument performance evaluation
Install and start the instrument correctly according to the start-up and initial adjustment
requirements in the instrument manual.
3.2.1 Determination of response factor
The response factor of various VOCs emitted by the emission source under test shall be
determined before use of the instrument. The response factor can be measured directly
or obtained from reference materials. After the response factor of the instrument is
determined, it is not necessary to repeat the measurement. The determination of the
response factor can ensure that the instrument has sufficient response to the VOCs that
need to be detected. When a known emission source emits a single VOC, the detection
value can be converted into the concentration of the compound through the response
factor of the compound.
instrument's sampling pump or sampling flow rate is adjusted and the instrument's
response time changes, the response time must be remeasured before use.
3.2.3.1 Introduce the zero gas from the sampling probe port. After the instrument
reading is stable, quickly switch to the calibration gas. Record the time required for the
instrument to reach 90% of the final stable display reading. Repeat this step 3 times.
The average value is taken as the response time of the instrument.
3.2.3.2 The instrument response time shall not exceed 30 s. When measuring the
response time, the sampling pump, dilution probe (if any), sampling probe and filtering
device shall be in place.
3.3 Wind direction anemometer
A wind direction anemometer of which the wind speed resolution is ≤0.1 m/s, the wind
direction resolution is ≤3°, and starting wind speed is ≤0.5 m/s.
4 Testing technical requirements
4.1 Instrument calibration
After the instrument is warmed up and zero gas calibrated, introduce the reference
compound standard gas for calibration into the instrument sampling probe. After the
instrument reading is stable, adjust the instrument reading according to the standard
value. If the instrument reading cannot be adjusted to a suitable concentration value, it
indicates that the instrument is faulty and shall be eliminated before use. Calibration
can be a single point concentration calibration. The single point concentration value
shall be close to the standard concentration limit. Multi-point calibration is also possible.
Standard concentration limits shall be within the range of calibration concentrations.
4.2 Sampling testing
4.2.1 Testing of leak sources
Place the sampling probe at the relevant part of the equipment or device where leakage
emissions may occur. Move along its periphery at a speed less than 10 cm/s. Also keep
an eye on the instrument readings. If you notice an increase in readings, slow down the
sampling probe movement until the maximum reading is measured. Stop at maximum
reading. The residence time is approximately 2 times the instrument response time.
Record the maximum reading. The sampling and testing regulations for leakage sources
are as follows.
4.2.1.1 Valves
The most likely place for a valve to leak is the seal between the valve stem and valve
body. Place the sampling probe at the valve stem stuffing box gland. Sample by moving
assumed that no detectable emissions are present. If there are emission points on the
pipeline where leakage may occur, background and source sampling shall be performed
to determine whether no detectable emission is present.
4.2.4 Leak detection procedures for other equipment
4.2.4.1 Use auxiliary detection methods such as infrared thermal imaging cameras,
Fourier transform infrared imaging spectrometers, and leakage ultrasonic
detectors
On the premise that the on-site conditions meet the testing requirements of the
instrument used, there is no interference, and the optical imaging instrument responds
to the VOCs emitted by the emission source to be measured, USE infrared thermal
imaging cameras, Fourier transform infrared imaging spectrometers, leakage ultrasonic
detectors, etc. to detect and scan the area of the equipment under test to quickly locate
possible leakage emissions. This type of method can be used to help locate the source
of leaking emissions at higher locations that are inaccessible to inspectors. After using
the above auxiliary detection method, the source to be measured that can be reached by
the detection personnel with the help of the extended sampling probe still needs to be
tested according to the requirements in 4.2.1 or 4.2.2.
4.2.4.2 Method of spraying soap solution to generate foam at the connections of
equipment where leakage may occur
This method is suitable for situations where there are no continuously moving parts, the
surface temperature of the equipment is not higher than the boiling point of the solution
or not lower than the freezing point of the solution, there is no excessively large open
area in contact with the air that would prevent soap bubbles from being produced, and
there are no significant traces of liquid leakage. If the above applicable conditions
cannot be met, testing shall be carried out according to the requirements in 4.2.1 or
4.2.2.
4.2.4.3 Spray soap solution on all possible leak points
Special leak detection soap solutions can be used OR a solution prepared with a certain
concentration of detergent and water can be used. Use a pressure sprayer or squeeze
bottle to spray the solution. Observe possible leak points for soap bubbles to form. If
no suds appear, it can be assumed that there is no discharge or leak. If soap bubbles
appear, testing shall be carried out according to the requirements in 4.2.1 or 4.2.2.
4.3 Recording and reporting requirements
The environmental conditions of the testing site, relevant meteorological conditions,
instrument and equipment calibration results, relative error results of indication values,
etc. shall be recorded in a standardized manner. Together with the test results, they serve
as the content of the test report.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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