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GB/T 17729-2023 (GB/T17729-2023)

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GB/T 17729-2023: PDF in English (GBT 17729-2023)

GB/T 17729-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 03.220.20; 13.040.99
CCS T 09
Replacing GB/T 17729-2009, GB/T 28370-2012
Hygienic Standard and Detect Methods for the Air Quality
Inside Interurban Bus
ISSUED ON: MARCH 17, 2023
IMPLEMENTED ON: OCTOBER 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Limits of Volatile Organic Compounds and Carbonyl Compound in New Interurban
Bus ... 6
5 Limits of Main Components of the Air in In-service Interurban Bus ... 7
6 Detection Methods for Air Quality in Interurban Bus ... 7
Bibliography ... 15
Hygienic Standard and Detect Methods for the Air Quality
Inside Interurban Bus
1 Scope
This document specifies the limits and detection methods for volatile organic compounds and
carbonyl compound in new interurban buses, and the limits and detection methods for the main
components of the air in in-service interurban buses.
This document is applicable to Class B and Class III buses in Category-M2, Category-M3. Other
types of buses may take this as a reference.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB 7258 Technical Specifications for Safety of Power-driven Vehicles Operating on Roads
GB/T 15089 Classification of Powder-driven Vehicles and Trailers
HJ/T 400-2007 Determination of Volatile Organic Compounds and Carbonyl Compounds in
Cabin of Vehicles
3 Terms and Definitions
What is defined in GB 7258 and GB/T 15089, as well as the following terms and definitions
are applicable to this document.
3.1 interurban bus
Interurban bus refers to a bus designed and manufactured for transporting passengers between
cities (urban and rural areas) and specialized in passenger transport.
[source: GB 7258-2017, 3.2.1.3.1.1, modified]
3.2 new interurban bus
New interurban bus refers to a newly produced interurban bus whose off-line time is within (42
 5) d and whose interior has not been changed.
3.3 in-service interurban bus
In-service interurban bus refers to an interurban bus that has completed registration and is used
for commercial road passenger transport.
3.4 volatile organic compounds
Volatile organic compounds are a generic term for volatile compounds collected by absorbents
like Tenex and separated by a gas chromatographic column with a polarity index less than 10,
and whose retention time is between n-hexane and n-hexadecane.
[source: HJ/T 400-2007, 3.2, modified]
3.5 carbonyl compound
Carbonyl compound refers to a compound with carbonyl functional groups, collected by 2,4-
dinitrophenylhydrazine (DNPH) and analyzed by high performance liquid chromatography.
[source: ISO 12219-1:2021, 3.4]
3.6 total volatile organic compounds; TVOC
Total volatile organic compounds refer to the sum of the values of volatile organic compounds
collected by absorbents like Tenax and separated by a gas chromatographic column with a
polarity index less than 10, and whose retention time is between n-hexane and n-hexadecane.
[source: GB/T 18883-2022, 3.4, modified]
3.7 aerobic plate count
Aerobic plate count refers to the number of microorganisms per cubic meter of vehicle interior
space after the air in the vehicle is sampled by an air microbial sampler and cultured under
certain conditions (such as: culture medium, temperature and time, etc.).
NOTE: colony count is expressed in colony-forming units (CFU).
[source: GB 4789.2-2022, 2.1, modified]
4 Limits of Volatile Organic Compounds and Carbonyl
Compound in New Interurban Bus
Table 1 specifies the limits of volatile organic compounds, carbonyl compound and total volatile
organic compounds (TVOC) in new interurban bus.
domestic vehicles. Under special circumstances, the test time may be determined in accordance
with the time of arrival in the Chinese market.
6.1.2 Sampling environment
The sampling environment where the vehicle under inspection is located shall satisfy the
following conditions.
a) Ambient temperature: 25.0 C  1.0 C.
b) Relative humidity: (50  10) %.
c) Airflow velocity is not greater than 0.3 m/s.
d) Background concentration in the sampling environment chamber: for a single type of
volatile organic compound and carbonyl compound, not greater than 0.02 mg/m3; for
total volatile organic compounds (TVOC), not greater than 0.2 mg/m3.
6.1.3 Setting of sampling points
The number of sampling points in the vehicle is determined by the effective volume of the
passenger compartment of the vehicle under inspection and the specific conditions of the
vehicle under inspection and shall be able to correctly reflect the air quality in the vehicle. The
setting of sampling points shall satisfy the following requirements:
a) For vehicles with a length of 9 m and below, there shall be at least two measurement
points, which are evenly arranged along the longitudinal centerline of the
compartment;
b) For vehicles with a length of above 9 m, there shall be at least three measurement
points, which are evenly arranged along the longitudinal centerline of the
compartment;
c) The height of the sampling points is 1.2 m  0.1 m from the plane height of the interior
floor.
6.1.4 Sampling devices
6.1.4.1 Sampling environment chamber
6.1.4.1.1 The sampling environment chamber is mainly composed of main chamber, air
conditioning system and filtration system, etc.
6.1.4.1.2 The inner surface of the sampling environment chamber shall be made of low-release,
low-permeability and low-absorption materials. Materials and facilities that may affect the
background concentration of environmental pollutants shall not be placed in the chamber. The
space in the chamber shall be sufficient to accommodate the vehicle under inspection, so as to
facilitate the personnel in the testing and sampling of the vehicle under inspection.
6.1.4.1.3 The sampling environment chamber shall take technical measures to reduce the
influence of airflow on the air exchange inside and outside the compartment of the vehicle
under inspection.
6.1.4.1.4 The main chamber shall be provided with a main door and an auxiliary door. The main
door shall ensure the normal entry and exit of the vehicle under inspection and shall not be
opened during the entire sampling process; the auxiliary door is provided for the safe entry and
exit of personnel. When the auxiliary door is opened throughout the sampling process, it shall
be ensured that the sampling environment conditions at least within a space of 0.5 m from the
outer surface of the vehicle under inspection satisfy the requirements of 6.1.2.
6.1.4.2 Sample collection device
6.1.4.2.1 The sample collection device is mainly composed of constant-flow gas sampler,
sampling conduit and packed column sampling tube, etc.
6.1.4.2.2 The flow rate of the constant-flow gas sampler shall be adjustable and stable within
the range of 50 mL/min ~ 1,000 mL/min. After connecting with the packed column sampling
tube, adjust the gas flow rate and use a primary flowmeter (for example, primary soap film
flowmeter) to calibrate the flow rate. The flow rate shall satisfy the requirement that the errors
before and after sampling are less than 5%.
6.1.4.2.3 The sampling conduit shall use treated stainless steel tubes, polytetrafluoroethylene
tubes or silicone rubber tubes. The air inlet shall be fixed at the specified sampling point in the
passenger compartment of the vehicle under inspection, then, lead the sampling conduit from
the passenger compartment, during which, the integrity and airtightness of the vehicle shall not
be damaged; the air outlet shall be connected to the packed column sampling tube outside the
passenger compartment. The end of the packed column sampling tube shall be connected to a
constant-flow gas sampler.
6.1.4.2.4 The airtightness of the entire sample collection device shall be guaranteed, and there
shall be no air leakage.
6.1.4.2.5 The packed column sampling tube shall comply with the relevant stipulations of
Appendix B and Appendix C in HJ/T 400-2007.
6.1.5 Sample collection procedures
6.1.5.1 Pre-treatment stage of vehicle under inspection
Put the vehicle under inspection into the sampling environment chamber, remove the surface
coverings used to temporarily protect the internal components of the vehicle, such as: the
protective film of seats and interior trim parts, etc. Completely open the doors and windows of
the vehicle under inspection, so that the vehicle can thoroughly communicate with the outside
air. In accordance with the requirements of 6.1.3, arrange the sampling points in the vehicle and
monitor the temperature of the sampling points inside the vehicle under inspection. After the
temperature reaches 25.0 C  1.0 C, the vehicle under inspection shall be put into the closed
6.1.9 Sample transportation and storage
The sampling tube shall be sealed with a sealing cap and tightly wrapped with tinfoil or
aluminum foil, stored and transported at low temperature (less than 4 C); the storage time shall
not exceed 30 d.
6.1.10 Determination and analysis
6.1.10.1 Determination of volatile organic compounds
The determination of volatile organic compounds shall be conducted in accordance with the
determination method specified in Appendix B of HJ/T 400-2007.
6.1.10.2 Determination of carbonyl compound
The determination of carbonyl compound shall be conducted in accordance with the
determination method specified in Appendix C of HJ/T 400-2007.
6.1.10.3 Calculation of concentration of total volatile organic compounds (TVOC)
TVOC includes the values of all compounds from n-hexane to n-hexadecane in the total ion
chromatogram (TIC). Calculate the concentration (Sid) of identified and quantified volatile
organic compounds in the standard curve; use the response coefficient of toluene to calculate
the concentration (Sun) of the first 25 maximum peaks of unidentified volatile organic
compounds; the sum of Sid and Sun is the concentration of TVOC.
6.1.11 Quality assurance and control
6.1.11.1 Instrument requirements
The instrument shall be timely calibrated and demarcated, pass the metrological verification
and be within the validity period.
6.1.11.2 Airtightness inspection
Before sampling, the airtightness of the sampling system shall be inspected, and there shall be
no air leakage.
6.1.11.3 Flow calibration
Before and after each sampling, a primary flowmeter (for example, primary soap film
flowmeter) shall be used to calibrate the sampling flow rate of the sampling system under
sampling load conditions.
6.1.11.4 On-site blank inspection
During each sampling, at least 2 blank sampling tubes shall be reserved as on-site blank during
the sampling process and sent to the laboratory together with other sampling tubes after
sampling. During sample analysis, determine the on-site blank value.
6.3.1.2 The impact-type air microbial sampler shall satisfy the following requirements:
a) The capture rate of bacteria in the air shall not be less than 95% (the pore size of the
sixth stage sieve shall not be greater than 0.3 mm);
b) It shall be easy to operate, easy to carry, stable in performance and convenient for
sterilization.
6.3.2 Nutrient agar medium
6.3.2.1 The ingredients include 20 g of peptone, 3 g of beef extract, 5 g of sodium chloride, 15
g ~ 20 g of agar and 1,000 mL of distilled water.
6.3.2.2 The preparation method is as follows:
a) Mix the ingredients in 6.3.2.1;
b) Heat to dissolve it;
c) Adjust pH to 7.4, filter and divide it;
d) At 121 C, perform autoclaving for 20 min.
6.3.3 Detection method
6.3.3.1 The setting of sampling points in the vehicle shall comply with the requirements of 6.1.3.
6.3.3.2 Before sampling, the doors and windows of the vehicle under inspection shall be closed.
Start the engine, tune the air conditioner to the maximum wind speed mode and turn on the air
purification device (if any). The vehicle under inspection is in the state of no-load and idle
speed. When the temperature inside the vehicle under inspection reaches the range of 20 C ~
30 C, start sampling.
6.3.3.3 Disinfect the sampler and arrange the sampling points, then, in accordance with the
instructions of the instrument, conduct sampling. The sampling volume is 30 L ~ 150 L. In
accordance with the performance of the instrument used and the degree of microbial
contamination of the air in the vehicle, the sampling volume of air shall be increased or
decreased as appropriate.
6.3.3.4 After sampling is completed, put the bacteria-carrying nutrient agar plate into a
constant-temperature incubator at 36 C  1 C, incubate for 48 h, count the aerobic plate count,
then, in accordance with the flow rate and sampling time of the sampler, convert it into the
number of colonies per cubic meter of air (CFU/m3).
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.