Q&A:

The issues to consider about Hazardous Area Classification (HAC) in Manufacturing

Question 1: What are the reference standards and application of HAC in Vietnam?

Currently, most Vietnamese standards refer to IEC standards, so you can apply the IEC-60079.

Question 2: How necessary is the application of HAC for our wood pellet factory?

The production of wood pellets creates flammable dust, which can pose a high risk of fire and explosion. When wood dust is suspended in the air, it can form explosive dust clouds that can be ignited by sources such as electrical sparks from the production process. Therefore, it is essential to implement Hazardous Area Classification for your factory.

Question 3: How much does it cost to implement this?

The implementation cost is mainly calculated based on the following information:
- Factory scale
- Scale of the technological process
- The amount of flammable and explosive substances involved in the entire production process of the factory
Customers will provide this information when requesting a service quote. We are always ready to discuss and consult with customers to obtain complete and accurate information for quotation.

Question 4: Is it necessary to do HAC if the equipment installed does not generate a source of ignition?

Not only do fixed equipment pose a risk of ignition, but also humans working in the same space. As a result, Hazardous Area Classification is essential. After zoning, your company will be able to manage the safety of people operating and working in this space, such as:
- Implementing proper working procedures in an explosive atmosphere
- Ensuring that employees are trained to work in this environment
- Managing and training external contractors before they perform work in this environment.

Question 5: I'm interested in verification/testing for Dampers according to SOLAS or ABS standard (in HVAC-R system). Please give me more information. Thank you.

We currently do not provide this service.

Question 6:What types of businesses can apply HAC? Can construction be applied?

The Hazardous Area Classification is based on the possibility of the existence of an explosive atmosphere. Therefore, any type of business that uses dangerous flammable materials and chemicals should carry out fire hazard zoning to clearly understand fire and explosion risks.

Question 7: How to determine the explosion threshold of organic dust in production?

Depending on the characteristics and parameters of each type of dust, there are different parameters to evaluate the flammability and explosion potential of that type of dust. If possible, can you provide more information about the type of dust you are interested in?

Question 8: What are the basic principles of controlling and detecting gas leaks in closed rooms and enclosed areas?
What is the current reliable device for detecting flammable liquefied gas leaks? I respectfully ask BVC to share and give comments?!

There are many methods to control liquefied gas leaks from design to operation. A common passive method is to install a gas detection system that detects gas after a gas leak into the environment (closed room). This system should be selected with advice from the supplier's experts. correctly, install the correct probe for each type of gas as well as the correct direction of gas dispersion when there is a leak to detect the leak early and promptly.

Question 9: What are the relevant Vietnamese/international standards for assessing fire and explosion thresholds due to organic dust?

Please see this standard: TCVN 6553-1:1999 (ISO 6184-1: 1985)

Question 10: Please explained to me in detail about static electricity, including:
- Conical pile discharge
- Propagating brush discharges
Thank you.

- Conical pile discharge: This type of large discharge is observed during the process of loading materials into a silo. This phenomenon occurs when the loaded powder disperses in the top of the silo, forming highly concentrated dust clouds and electrical charges. Focus on these clouds. When the charge is large enough, there will be an electrical discharge between the clouds or between this cloud and the silo wall.

- Propagating brush discharges: a phenomenon in plastic flour containers/bags that can be dangerous due to the formation of capacitor-like electrical layers on the walls during the filling process. An example of this phenomenon is the charge stored outside the wall of a tank that discharges static electricity to a metal support frame.

Question 11:
a, Is it necessary to separate the packaging (PE, paper, carton, ...) and the product (fried dough)?

This distribution depends on many different factors required by the factory. Regarding Hazardous Area Classification (HAC), you should consider the characteristics of the flammable substance, which could be frying oil, cartons, etc., to know the possibility of an explosive atmosphere. From these assessments, you will decide whether the partition is an explosive zone or not as well as whether there should be separation between these zones or not. If an explosive atmosphere does not exist, it can be considered a safe zone and no need to be separated anymore.

b, Our factory uses Oil to run boilers and forklift tanks. They create a bad smell when charging the tanks. Is it necessary to zone and provide solutions to minimize fire risks?
Similar to the answer above.

c, Our factory has fine powder (wheat flour and flour after drying), is there a risk of fire and explosion? Are there any measures needed?
Similar to the answer above.

Question 12: My factory specializes in tungsten production, uses many chemicals, and we only find out zone 2 for areas that generate H2S and NH3 gases. Is this right?

You should consider Hazardous Area Classification for the entire factory. If that place does not have the possibility of an explosive atmosphere, that place will be classified as a safe zone.

Question 13: Our company is an organizational complex including a production area, warehouse and transportation area for the agricultural industry.
So how to develop important goals as well as how to do HAC from the beginning which areas are dangerous explosion zones?

Regarding Hazardous Area Classification (HAC), you should consider the characteristics of flammable substances at different places in the production line to know the possibility of an explosive atmosphere. From these assessments, you will decide what zoning that area has. If there is no explosive atmosphere, it can be considered a safe zone.

Question 14: Regulations on electrical equipment installed in Zone2 area. Regulations according to which TCVN standard?

Currently, most Vietnamese standards refer to IEC standards, so you can apply the IEC-60079 series.

Question 15: How to control ol of arising work related to Work Permit in different dangerous zones (Z0, Z1, Z2)?  Please give an example.

This is based on a risk assessment of the plant after zoning is obtained. Methods to minimize risks related to Work Permits, can be as follows:

- Operating procedures

- Safe working principles

- Train and ensure the capacity of company employees as well as contractors working in dangerous zones.

Question 16: My business is in the seafood industry and uses wood to burn a boiler to create heat for the hot water system, does it need fire zoning?

You should consider doing Hazardous Area Classification for the entire factory. If that place does not have the possibility of an explosive atmosphere, that place will be classified as a safe zone.

Question 17: How to calculate the scope of each zone and what factors are used to calculate it? Thank you.

You can refer to the instructions of the standards mentioned in the webinar slides.

Question 18: To limit the risk of explosion in a closed space (Silo...), the factory will install explosion-proof glass. When it explodes, it will explode in the direction you choose.
But in case the pressure of the device to be attached is greater than the force of the explosion-proof glass (which means that when attached, the glass will continuously break). Are there any solutions for these cases? Thank you.

To add additional devices to minimize or direct dust explosions during the slow explosion phase, you should first consult the equipment manufacturer to understand the technology as well as gain knowledge about dust explosions. Usually, the equipment supplier is the one with the most suitable technical requirements. Suppliers have experience and case-specific testing types for the devices they produce.

Question 19: I don't understand the technical part: "Fuel Air Mixture too rich = No fire possible" because I think the more it is, the more flammable it is. Please explain, thank you!

Fire is a chemical reaction between combustibles and oxygen in the air. If the air ratio is too low, resulting in too low an oxygen concentration, the reaction cannot occur even if there is a heat source.

Question 20: For the factory where we are producing packaging from plastic beads (tubes, bottles), in my opinion, the grinding step will create a lot of plastic dust in the air and this step is located close to the warehouse wall.
In addition, the grinding area itself is relatively more ventilated than the warehouse (fans, natural air blowing in). So are there any tools or methods that BV can suggest?

Regarding Hazardous Area Classification (HAC), you should consider the characteristics of flammable substances (plastic dust) at production line locations as well as adjacent ventilation areas to determine the possibility of the atmosphere existing. explosive gas. From these assessments, you will decide what zoning that area has. If there is no explosive atmosphere, it can be considered a safe zone. 

Question 21: What tool does Bureau Veritas use to determine HAC?

Normally, BV uses MS office suite to perform hazard zoning. If it is necessary to model the process of spreading explosive and dangerous gases, BV will use PHAST software.