Fire Safety Solutions for Urban Comprehensive Pipe Gallery

Preface to Fire Safety Solutions

Before we introduce the fire safety solutions, let’s take a look at the urban comprehensive pipe gallery first.

The urban comprehensive pipe gallery sometimes called the “utility tunnel“, originated 200 years ago in European countries such as France and the United Kingdom, and later spread to Asian countries such as Japan and China.

Comprehensive pipe gallery refers to the construction of a municipal public tunnel under urban roads, which gathers various municipal pipelines such as electricity, communication, water supply, and gas together to achieve comprehensive utilization and resource sharing of underground space.

Pipe Galleries or tunnels are usually 2-4 meters high and 2-4 meters wide, built at a depth of approximately 6 meters underground.

The types are divided into branch type, trunk type, and cable type.

In China, the government advocates for everyone to focus on building urban underground comprehensive pipe corridors, so in recent years, the business of comprehensive pipe corridors in various cities has developed rapidly.

To correctly select suitable automatic fire extinguishing equipment, a comprehensive analysis should be conducted from the aspects of product composition, main characteristics, working principle, fire extinguishing mechanism, and basic design parameter requirements, to determine a fire extinguishing equipment product with stable quality, safety and reliability, high fire extinguishing efficiency, and high cost-effectiveness.

The selection of a fire extinguishing system is also a key point for comprehensive pipeline corridor fire protection, At present, several types of fire extinguishing systems are more suitable for comprehensive pipeline corridors: water mist system, foam fire protection system, gas fire extinguishing system, aerosol fire suppression system, and ultra-fine dry powder fire extinguishing system.

Water Mist System

The water mist system is divided into low pressure, medium pressure, high pressure, and water spray, No matter what type of fine water mist, it is not very suitable for use in urban underground comprehensive pipe galleries, because the disadvantage is that it occupies relatively limited space in the pipe gallery, The fire extinguishing speed is relatively slow, and after spraying, the water will corrode and damage the electrical facilities in the pipe gallery.

A water pump room needs to be set up every other distance, which would be very inconvenient.

Moreover, the underground comprehensive pipe gallery requires a dry environment, so a fine water mist system is not recommended.

Foam Fire Protection System

Foam systems are similar to water mist systems, It is made of foam and water in a certain proportion.

Generally, foam fire extinguishing devices have one or several large storage tanks. This type of piping takes up a lot of space and is also piped.

The foam system also has a complex structure, similar to the water system, which is not an ideal choice for underground utility tunnel fire protection.

Gas Extinguishing System

The scope of gas fire extinguishing systems is relatively broad, mainly including carbon dioxide, inert gas, NOVEC 1230, FM200, etc.

The gas system cannot be used for the comprehensive pipeline gallery either, because they have the following disadvantages:

• Gas thermal expansion, which may cause explosion, and may harm personnel and circuit safety.
• Most gas systems are composed of pipe network systems, which are very complex and difficult to lay.
• Gas is prone to leakage and requires frequent inspection, which is also very difficult.
• Long-distance gas transportation leads to a decrease in pressure.
• A large number of gas storage stations need to be built, which is costly in terms of investment.
• Gas cylinder storage rooms need to be set up every 100-200 meters

Aerosol Fire Suppression System

The aerosol fire extinguishing system has no pipe network, no pressure, and no corrosion, making it a suitable fire extinguishing system for pipe galleries.

The vast majority of urban comprehensive pipe galleries can use aerosol suppression systems, but not in areas with temperature requirements, as aerosols generate a certain temperature during spraying.

Compared with dry powder systems, the advantage of aerosol systems is that there are no residues; The disadvantage is that the temperature is very high during spraying.

The wall-mounted aerosol fire extinguishing device is very suitable for pipe galleries.

Superfine ABC Dry Chemical Powder System

Super-fine ABC systems can be divided into pressurized type and non-pressurized type.

The non-pressurized type is currently the most suitable fire extinguishing system for comprehensive pipeline corridors.

Compared to aerosol systems, it does not generate high temperatures and is very safe and reliable.

We have listed some of its benefits below:

• It can be mounted on top of the pipe gallery with an R-shaped hook and will not take up space.
• It can work independently without other auxiliary accessories.
• It can be connected by multiple devices and can also be connected to a fire alarm control system.
• He immediately extinguishes the fire after starting and is stored at room temperature. When not working, there is no pressure, so there is no need to worry about the safety of the inspectors.
• It can protect the pipeline gallery facilities locally or in sections, which is very practical and convenient.

However, its biggest drawback is that it produces a white powder that makes it difficult to clean.

Even if it has its drawbacks, it does not affect its becoming the first choice for pipe gallery fire protection.

At present, in China and abroad, the vast majority of pipeline gallery projects use non-pressurized storage ultra-fine powder extinguishing systems.

Final Summary

In summary, both aerosols and dry powder can become fire protection solutions for urban underground pipeline corridors. If you want to rank, ultra-fine dry powder is the most suitable, followed by aerosols.

Many facilities in underground comprehensive pipe galleries can install non-pressurized super-fine ABC dry powder extinguishers, including cable trenches, cable trays, and cable tunnels.

There are a lot of various types of switchboards(distribution cabinets) in the complex, so we can install small-sized aerosol fire extinguishers in these switchboards(distribution cabinets).

The combinations of aerosols and dry powder are the perfect fire safety solutions for urban underground comprehensive pipe corridors.

If you have different opinions and perspectives, please feel free to comment and discuss.