HG/T 20510-2014Design code for instrument air engineering (English PDF)

Foreword

This code was revised in accordance with the requirements of the "Notice on Issuing the First Batch of Industry Standard Development and Revision Plans for 2010" of the Ministry of Industry and Information Technology (Gong Xin Ting Ke [2010] No. 74) and of the "Notice on Forwarding the Notice of the General Office of the Ministry of Industry and Information Technology on Issuing the First Batch of Industry Standard Development and Revision Plans for 2010" of the China Petroleum and Chemical Industry Federation (Zhong Shi Hua Lian Zhi Fa [2010] No. 222). The revision was organized by the National Chemical Industry Automatic Control Design Technical Center Station, entrusted by the China Petroleum and Chemical Engineering Survey and Design Association.

From its date of implementation, this code replaces "Regulations for instrument air supply design" HG/T 20510-2000.

The drafting group revised this code after extensive investigation and research, conscientious summarizing of practical experience, reference to relevant international standards and advanced foreign standards, and wide consultation.

The main technical contents of this code are: the design methods and requirements for the air supply of measuring and control instruments in chemical plants.

Compared with HG/T 20510-2000, the main changes of this code are as follows:

1. The formulas for conversion between standard conditions and operating conditions in the calculation of air consumption have been deleted.

2. The formula for calculating the capacity of the air source unit and the formula for calculating the volume of the air receiver have been revised.

3. "Outlet pressure of the air source unit" has been revised.

4. "Safe air supply" has been revised.

5. "Table of selection ranges of pipe sizes for air supply system piping" has been revised.

This code was proposed by and is under the jurisdiction of the China Petroleum and Chemical Industry Federation.

Sedin Engineering Co., Ltd. is responsible for the interpretation of the technical contents of this code. Any comments and suggestions arising in the course of implementing this code should be sent to Sedin Engineering Co., Ltd. (address: No. 1 Saiding Road, Hi-tech Zone, Taiyuan, Shanxi Province; postcode: 030006) for reference in future revisions.

Chief editorial organization of this code: Sedin Engineering Co., Ltd.

1 General provisions

1.0.1 This code is formulated in order to unify the technical requirements for instrument air supply in the chemical industry, to promote the standardization of instrument air supply engineering design, and to achieve the objectives of advanced technology, economic rationality, safety and suitability for use.

1.0.2 This code is applicable to the air supply design of measuring and control instruments of chemical plants.

1.0.3 The loads of the instrument air supply system include air for pneumatic equipment such as pneumatic instruments, pneumatic actuators and electro-pneumatic converters, air for pressurized ventilation for explosion protection, air for the commissioning and repair of pneumatic instruments in the instrument repair workshop, air for instrument purging, etc.

1.0.4 Clean and dry compressed air shall be used as the instrument air source. In emergencies, nitrogen may be used as a temporary air source.

1.0.5 In addition to complying with the requirements of this code, instrument air supply design shall also comply with the provisions of the current relevant national standards.

2 Terms

3 Quality of instrument air

3.0.1 The dew point of the air source of the air supply system at operating (line) pressure shall be at least 10 °C lower than the extreme minimum temperature of the working environment or the historical local annual (seasonal) extreme minimum temperature. For dew point conversion see Figure 3.0.1.

Figure 3.0.1 Dew point conversion chart (dew point at operating pressure, °C, against dew point at atmospheric pressure, °C)

3.0.2 The particle size of dust in instrument air shall not exceed 3 um, and the dust content shall be less than 1 mg/m3.

3.0.3 The oil content of instrument air shall be less than 1 ppm.