GB/T 35528-2017Safety guidelines for cryogenic liquefied gases (English PDF)

3.1 Terms and definitions

The following terms and definitions apply to this document.

3.1.1 Gas

Substances with a vapor pressure greater than 300kPa at 50°C; or substances that are completely gaseous at a standard pressure of 101.3kPa at 20°C.

3.1.2 Compressed gas

Substances that are completely gaseous when packed under pressure for transport at - 50°C. This category includes all gases whose critical temperature is less than or equal to -50°C.

3.1.6 Accident resulted from human error

Accidents caused by the unintentional act of an operator.

3.1.7 Chain reaction accident

A series or chains of accidents arising from a local accident or a single accident.

3.1.8 Risk assessment

At the beginning of the design, an evaluation of the expected use of the device and equipment after a certain period of time and the possible failure modes under various operating conditions.

4.1 Establishment approval

The establishment of cryogenic liquefied gas device shall comply with the provisions of "Measures for the Safety Supervision and Administration of Hazardous Chemical Construction Projects" [6] of State Administration of Work Safety.

4.3 Safety protection system

To detect and prevent accidents and minimize the risk of personal and property damage accidents, safety guards shall be installed in every link from product packaging to use.

Configure various safety facilities including firefighting equipment. Personal safety protection facilities for on-the-job staff shall also be complete.

4.4 Alarm system

Necessary alarm devices shall be installed to monitor abnormal changes in temperature and pressure of the associated cryogenic equipment. Detect abnormal changes in the concentration of stored cryogenic liquefied gas in the surrounding air. Provide timely alerts before accidents occur.

4.5 Safety certificate

Cryogenic liquid devices and related equipment, electrical instrument control systems, storage and transportation units as well as power supply systems, before being put into normal use, shall pass the safety performance certification not lower than that of the prefecture-level safety supervision agencies.

4.7 Safety training

It shall, according to the provisions of the "Work Safety Law of the People's Republic of China"[1], "Regulations on the Safety Management of Hazardous Chemicals"[3], "Regulations on the Administration of Safety Technology Training and Assessment for Special Operators"[5] and "Safety Training Regulations on Producers and Operators"[4] of State Administration of Work Safety, carry out targeted safety education, legal education and job technical training for cryogenic liquid practitioners, based on different jobs.

4.8 Safety inspection System-wide

safety inspection shall be carried out before the cryogenic liquid device is put into production. The inspection includes the implementation of the safety measures specified in 4.1~4.7.

5.1 Design qualification

The organization that undertakes the design of the cryogenic liquefied gas device, including the filling and storage system, the transportation unit and the required special equipment, must pass the review of the design qualification assessment agency authorized by the General Administration of Quality Supervision, Inspection and Quarantine. Design can only be done after obtaining the corresponding design qualifications.

5.3 Principle to avoid accident resulted from human error

Reasonable safety control methods shall be adopted in the design, so as to reduce and eliminate safety accidents that may be caused by human errors in all links from product packaging to use.

5.4 Principle to avoid chain reaction accident

Reliable solutions or measures shall be taken during design, so that a partial failure or accident does not lead to a series of failures or chain reaction accidents.

5.5 Risk assessment

For all pressure containers involved in cryogenic liquefied gas device, the organization with the corresponding equipment design qualification shall provide the risk assessment report and propose corresponding safety measures to control the risk according to the requirements of GB/T 150.1.

5.7 Safety distance

The fire safety distance between cryogenic liquefied gas storage tanks and various buildings and structures, as well as the safety distance between storage tanks, shall be implemented in accordance with the provisions of GB 50016, GB 50030 and GB 50177.

6.1 Containers for filling and storage

There are many types of containers or equipment used to fill and store cryogenic liquids.

There are stationary cryogenic tanks and mobile cryogenic containers. Usually, stationary tanks have a relatively large capacity.

6.2 Stationary cryogenic liquid filling and storage system

6.2.9 Fireproof

Smoking is prohibited around liquid hydrogen, liquid methane and liquid oxygen storage tanks. It is strictly forbidden to place any flammable substances in these storage tanks, special liquid pumps, vaporizers, related valves, pipes and their exhaust gas outlets.

6.2.12 Restricted operation

Only trained and qualified personnel shall perform cryogenic liquid storage, transfer and transfer operations. See Chapter 10 for personal safety protection during the operation of equipment in contact with cryogenic liquids or during the transfer and delivery of cryogenic liquids.

6.3 Mobile cryogenic liquid storage system

6.3.5 Large and medium-sized mobile cryogenic equipment

Large and medium-sized mobile cryogenic storage tanks adopt vacuum or multi-layer vacuum insulation structure. It consists of an inner tank and an outer shell with a vacuum interlayer. The nominal volume of the internal tank used for filling the cryogenic liquid medium is equal to or greater than 450L.

6.3.6 Cryogenic liquid railway tank car

The design, manufacture, inspection and use management of cryogenic liquefied gas railway tank cars and their tanks shall comply with GB/T 10478, TSG R0005 and the relevant regulations of the railway transportation authority of the State Council at the same time.

6.4 Mobile cryogenic container safe filling technology

6.4.1 Filling method

For the filling of mobile cryogenic containers with specified cryogenic liquefied gases from cryogenic liquid production units or stationary cryogenic liquid storage systems, three different methods can be used, that is, gravity dump, pressure dump and cryogenic liquid pump dump fill. For different dump filling methods, corresponding safe filling techniques shall be adopted.

7.1 On-site short-distance transportation

7.1.1 Small mobile cryogenic container transfer

After the small mobile cryogenic container in the workplace is filled with liquid, for Dewars filled with cryogenic liquids and cryogenic liquid welded insulation cylinders, shock-resistant carts or similar specialized equipment shall be used to transport. When in use, the Dewar or gas cylinder shall be fixed on the cart with straps to prevent it from slipping. It shall not be transported by means of dragging, pulling, rolling or throwing.

7.2.1 Transport or escort personnel

The relevant personnel responsible for the transportation or escort of cryogenic liquefied gas shall have received specialized technical training and obtained transportation license.

7.2.2 Hazard pictogram signs

According to the provisions of GB/T 24774, the classification of cryogenic liquefied gases packaged for transportation shall be marked with hazard pictogram signs.

7.2.5 Regular inspection during transit

The inspection items are basically the same as the inspection items before shipment.

7.2.6 Emergency discharge

When it is necessary to urgently discharge a large amount of cryogenic liquefied gas during transportation, quickly leave the vehicle concentration point. Leave industrial and mining areas and densely populated areas.

7.2.7 Intermodal transportation requirements

The business process will involve the long-distance transportation of cryogenic liquids and the intermodal transportation of multiple means of transportation.

7.3 Rail transport

7.4.4 Liquid inert gas

Liquid nitrogen, liquid helium, liquid neon, liquid argon and liquid krypton are all transported as Class II dangerous goods.

7.4.5 Driving speed

When driving on the highway, the driving speed shall not be higher than 80km/h. The speed driving on primary and secondary roads shall not exceed 50km/h. The speed driving on ordinary roads shall not be higher than 30km/h. The speed driving on dirt roads shall not be higher than 20km/h.

8.1 Code for safe operation of liquid flammable gases

8.1.1 Operating site

The flammable liquid gas products to which this Standard applies are liquid hydrogen and liquid methane.

8.1.2 Building design requirements

When flammable and explosive cryogenic liquids and gases are used indoors and buildings with open walls, in addition to setting the self-flow exhaust port of the louver and installation of alarm probe, a positive pressure mechanical ventilation system shall also be provided at the top of the building.

8.1.3 Pressure reducing and relief valve

Any container for loading and using liquid hydrogen or liquid methane shall be equipped with corresponding pressure relief valve. This valve must not only discharge over-pressured hydrogen vapor or methane vapor, but also prevent air from entering.

8.1.7 Pipeline velocity

The safe flow rate of liquid hydrogen and liquid methane in the pipeline varies according to the fluid pressure. Usually, it is between 0.2m/s~1.2m/s. The highest shall not be greater than 1.5m/s. The maximum allowable flow rate of gas in the hydrogen pipeline shall be implemented in accordance with the provisions of GB 50177. The maximum allowable flow rate of gas in the methane pipeline can be implemented with reference to the provisions of GB 50177.

8.1.12 Anti-suffocation

Hydrogen and methane are a choking hazard to humans. See 8.3 for specific precautions during use.

8.3 Specifications for safe operation of liquid inert gases

8.3.1 Asphyxiation

All inert gases, like hydrogen and methane, do not support breathing and pose a suffocation hazard to the human body.

8.3.2 Operating site

The requirements for the installation, use and accident handling of large storage equipment such as liquid nitrogen and liquid argon shall be governed by the provisions of JB/T 6898.

9.1 General

9.1.1 Fire prevention plan

The fire prevention plan shall include fire extinguishing steps and rescue measures after a fire occurs.

9.1.2 Fire training and drills

To avoid panic in the event of a fire, a full-time or part-time safety officer shall be set up. Conduct fire safety training for employees. Perform regular maintenance of fire equipment. Hold firefighting drills when necessary. If necessary, joint drills shall also be held in coordination with the local fire department.

9.1.4 Additional fire protection measures

Among the cryogenic liquids listed in this Standard, hydrogen and methane are flammable gases, which have direct fire hazards and hidden dangers.

9.1.5 Fire separation distance

Smoking or use of open flames is strictly prohibited around liquid hydrogen, methane and oxygen operations. The minimum distance from the open flame is. 150m for liquid hydrogen, 150m for liquid methane, 50m for liquid oxygen.

9.1.6 Extinguishing agents

Extinguishing agents suitable for different cryogenic liquid fire environments are shown in Table 1. […]