GB/T 25749.1-2010Safety of machinery -- Evaluation of the emission of airborne hazardous substances -- Part 1: Selection of test methods (English PDF)

3.1 Uncontrolled emission rate of a given pollutant

mu The mass of pollutants emitted by the machine into the surrounding space per unit time.

Note: It is not appropriate to take any measures to reduce air pollution around the machine (for example. capture devices, sealing equipment, humidification).

3.2 Controlled emission rate of a given pollutant

mk The mass of pollutants emitted by the machine into the surrounding space per unit time when measures to reduce air pollution are taken.

Note: Measures should be taken to reduce air pollution around the machine (for example. capture devices, sealing equipment, humidification).

3.3 Capture efficiency

The difference between the mass flow rate of a given pollutant collected directly by the pollutant control system and the uncontrolled mass flow rate of that pollutant emitted by the machine ratio.

Note 1. The capture efficiency can be calculated by the following formula. mu-mk mu ×100% (1)

This formula applies only if mu-mk represents the mass flow of pollutants captured directly. When emissions are affected by the control system, this parameter does not Be applicable.

Chapter 3), different test methods may be considered. The test method should be selected according to the following criteria.

--- the type of pollutant used;

--- Type of test environment.

ISO 3966, GB/T 2624.1, ISO 5168 are suitable for measuring fluid flow.

4.2 Types of pollutants used

Tests should be performed using actual contaminants whenever possible. However, in some cases, it is more convenient to use the tracer technique for testing. to actual pollution The addition of dyes to tracers needs to meet several conditions, especially the comparability of emission and flow patterns of actual pollutants and tracers.

Depending on the test method, two types of contaminants should be considered.

--- aerosol (solid or liquid) or gaseous actual pollutants;

--- Tracers that simulate actual pollutants.

When determining the actual pollutant emission rate without measuring air flow, both the actual pollutant and the tracer are used. Concentration measurements can be made by.

--- Measured together with air flow in the duct;

--- Measure at a position around the machine under test.

4.3 Types of test environments

4.3.1 Overview

There are two main types of environmental test conditions that can be considered, and in some cases different test methods may be required.

4.3.2 Laboratory method

4.3.2.1 Test bench method

Carry out the test in a test chamber specially designed for these tests or measurements, the size of the test chamber should be limited and known.

To prevent other machines from affecting the contamination conditions around the machine being inspected and interfering with the air flow through the contamination control system, the test chamber is only Place a machine.

The air flow pattern around the machine should be maintained by the specified general ventilation conditions of the test chamber.

NOTE: In such methods, the overall ventilation conditions and machine operating conditions are determined and to a certain extent random. Therefore, in most cases, they are not represents the actual situation encountered.

4.3.2.2 Indoor method

Tests are carried out in a chamber located in a laboratory or on-site at an industrial plant and dedicated to these tests or measurements.

Only one machine should be running at a time. Compared with the on-site method, this method can control the general ventilation and local ventilation more accurately. because the machine The position of the machine is not fixed, so in order to determine the effect of cross-air flow, the airflow pattern around the machine should be checked.

NOTE: In such methods, the overall ventilation conditions and machine operating conditions are determined and to a certain extent random. Therefore, in most cases, they are not represents the actual situation encountered.

4.3.3 On-site method

Many machines are too large to handle or have special installation or workmanship requirements and cannot be used in a test chamber (see 4.3.2.1) or indoors (See 4.3.2.2) to carry out the test, the test can be carried out at the installation site of the machine.

Due to the need to take into account various disturbances (such as cross-air flow) that occur in practical situations, the field is carried out in the usual working environment of the machine. Experimentation is especially important.

Before and during the test, care should be taken to determine the operating conditions of the machine to be tested and its pollutant control system, as well as the contamination effects of the test.

The operating conditions of other machinery based on the test results.

NOTE: This effect can be avoided by using a suitable tracing method.

The operating conditions of inspected machines and other equipment should be recorded.

Additional measurements are required to assess the characteristics of general ventilation including air cross-flow. For example, crossovers caused by door openings Airflow can severely interfere with airflow patterns around the machine.

4.4 Method summary

A detailed description of each method is given in the various parts of GB/T 25749 listed in Table 1. Additional information on more specific test conditions will be Available in a Class C standard for a specific class of machinery.

5.1 Overview

In situations where several methods appear to be suitable, the following factors should be considered in selection.

--- Determination of evaluation parameters that are comparable between machines and between pollutant control systems;

---Relevance of foreseeable machine working locations to the chosen method.

5.2 Choices related to evaluation parameters

The selection of the most appropriate parameters depends on the information needed, and one or more evaluation parameters are determined to satisfy this need.

a) For a specific machine and its pollutant control system, this requirement may be a comprehensive assessment of the emission of a given pollutant. Can be given by the following parameters.

--- Given the controlled emission rate of pollutants (mk), or represented by the following parameters.

--- Pollutant concentration parameter (PC).

b) For capture devices, separation equipment or more conventional pollutant control systems, a single parameter is sufficient to evaluate the following performance.

--- For capture devices, capture efficiency (eta C);

--- For separation equipment, it is the mass separation efficiency (eta S);

--- For a given machine's pollutant control system and no air recirculation, the purification index (IA).

c) A further analysis of the same requirement can determine the role of each component (machine itself, capture device, separation device), which requires measurement Two or three arguments.

--- uncontrolled emission rate for a given pollutant (mu);

--- Capture efficiency (eta C);

--- Mass separation efficiency (eta S).

5.3 Choices related to test environment

According to the criteria given in 5.2, the following practical and obvious factors should be considered in the selection of the test environment.

---Machine size;

---The difficulty of moving the machine;

--- Ease of installation, including machine pollution control systems;

---Easy to operate;

--- The nature of the pollutant. whether it is toxic and the complexity of the concentration measurement.

NOTE: Some difficulties can be overcome by the tracer method.

If a test chamber is used, it is recommended that the maximum cross-sectional area of the machine should not exceed 1/5 of the cross-sectional area of the test chamber.

5.4 Choices related to pollutant categories

By definition, actual pollutants are necessary to determine discharge rate, separation efficiency, pollutant concentration parameters and purification index.

In some cases, tracer techniques are more convenient to determine certain parameters for the following reasons.

--- There is no experimental difficulty caused by background concentration;

--- Special test equipment (sampling equipment, analytical instruments).