Rubasse Blog

Roasting Safety | Heat Source Should be Highly Concerned

413 | 2020-09-26

EBC News | Coffee Roaster Gas Explosion Turned a Part-time Worker into Vegetative State

On December 31, 2014, a female student named Hsieh, who was in her 20s, was working in the coffee chain store in Taipei City (now closed). When operating the coffee roaster, she left the seat once turning on the fire. However, she didn’t know the roaster had not to be lit yet at the moment. When she turned back and tried to turn it on again, the roaster suddenly blew up and caused a gas explosion. On the spot, her hair and eyebrows were burnt, and even her face was second-degree burnt. Immediately sent to the local hospital as she was, she still became a vegetative person due to hypoxic encephalopathy.

Afterwards, Hsieh’s father accused the coffee shop (CAMA) manager and the doctor of negligent assault. However, Taiwan Taipei District Prosecutor confirmed that Hsieh had received employee training and the doctors also did proper disposition.

CTI News | Overheated Coffee Roaster Caused Fire

Fire alarm news! The fire broke out in a well-known sightseeing tea factory in Nantou at around 8 am. The fire expanded very fast and the restaurant attached to the tea factory was almost burnt into scrap iron. The fire area was about 400 square meters! Due to the high altitude on the site, it is not easy to get water, and the firefighters could only draw the irrigation water nearby to meet the emergency need. Initial investigation shows the ignition point is on the second floor of the tea factory and the fire might cause by the overheated roaster.


 

Why Gas Explosions happen a lot?

The gas accidents mostly seen in the news are carbon monoxide poisoning caused by the gas explosion or incomplete combustion. Such accidents cause many regrets every year, and most of them are due to man-made negligence.

Because of this, we need to pay great attention to the safety problem while roasting. The heat source of the roasters in the market can be mainly divided into electric heating and gas. The electric heating is generally used to generate heat by a tubular electric heating element. The gas-type roasters, as the name implies, is to ignite gas just like the gas stove in the kitchen.

Because using gas-type roaster must operate with gas, we need to pay more attention. The more commonly used is liquified petroleum gas. When igniting, we need to keep eyes on whether it gets to light. It is also important whether the staff is able to handle the emergencies, such as being aware of if the fire source suddenly extinguishes in time or if the pipeline is damaged. Various factors may cause gas leaks in a confined space or a closed container (roaster). To a certain concentration, if encountering sufficient heat source, it may cause fires or even explosion hazards.

 

Gas Poisoning? Carbon Monoxide Poisoning?

Gas is an alkane gas, which is colourless, odourless, tasteless and non-toxic. Inhalation does not cause death. Common carbon monoxide poisoning is caused by burning in a confined space or in poorly ventilated areas, resulting in incomplete combustion and generating carbon monoxide.

Carbon monoxide, which is a colourless, odourless, tasteless, but toxic gas. People might get poisoned unconsciously by accident.

The capability to combine haemoglobin in carbon monoxide and red blood cells is 230 to 270 times that of oxygen. Therefore, once they are combined, it may cause tissue hypoxia and even seriously lead to death.

▼ Mild: The concentration of carbon monoxide in the blood is less than 30%. There may be symptoms such as headache, dizziness, nausea, vomiting, limbs weakness, fatigue, etc., such as cold or gastroenteritis.

▼ Severe: the concentration of carbon monoxide in the blood is greater than 30%, may have lethargy, blurred vision, accelerated breathing, arrhythmia, myocardial hypoxia, dyspnea and other reactions, because the symptoms of carbon monoxide poisoning often are mistakenly taken as fatigue. Therefore, people may just fall asleep and finally enter a coma and even worse end with death.

Therefore, the open fire should be placed in a well-ventilated place to avoid the risk of incomplete combustion and poisoning.

 

If Smelling Gas, What to do?

The hazard of gas is that it’s flammable and easy to be detonated. The explosions are powerful enough to ruin the neighbourhood. Therefore, odour stimuli are often added to natural gas to facilitate the locating of gas leaks and to remind people to pay attention to it.

In order to effectively avoid the risk of gas explosions, the gas barrel should be placed outside the house and well ventilated and not exposed to direct sunlight. Thus, the location must be carefully selected.

▼ Shut down the fire source: It is forbidden to use any fire source and electrical appliances, and it is not allowed to use electric fans or range hoods.

▼ Close the cylinder valve: Check the gas stove, water heater, close the valve, or wrap it with the tape first.

▼ Open the window: Slowly open the window (to avoid friction and spark), let the air flow naturally.

▼ Call out: If you can’t locate the gas leaks, call 911 immediately, or inform the gas supplier to check.

 

When Gas Explosion Happens, We Still Have Time to Escape?

If unfortunate encountering an explosion, whether it is a gas explosion or any type of explosion, you should immediately lower your body and turn your back on the explosion point, and protect your head with both hands to minimize the risks of getting injured.

Once the explosion ends, leave the spot as soon as possible to prevent yourself from getting injured again. While moving, try to avoid the windows, pillars, glasses, etc., and keep calm with the nose and mouth covered as well as lower the body and move as quickly as possible.

 

Hazard Prevention Once and for All

When it comes to the gas explosion accidents and the cases mentioned above, what we really need to focus on is not what to do when a disaster strikes. However, accidents happen in unforeseen things. Thus, we can’t be too careful because everyone may get a slip. What we can do is to reduce the risk and avoid the disaster happens. Otherwise, it just cures the symptoms, not the disease.

We believe everyone knows to avoid carbon monoxide poisoning in the bathroom. The gas water heater must be installed in a ventilated place, balcony, or even replaced with an electric water heater. To avoid gas problems in the kitchen, we can replace the gas stove with an induction cooker.

However, the use of coffee roaster is the same. We must choose the roasters with active safety design and/ or without the safety concerns mentioned above.

Most importantly, it is everyone’s responsibility to reassure the family while you are engaging in any works or interests.

 

Gas-type Roaster

Ignition system: Electric pulse igniter

This is the most commonly used electric pulse igniter, which generates a high voltage through the internal electronic components, and further generates sparks at the tip of the ignition needle, and ignites the gas. The main advantages are it is small in size, easy installation, and the economical price.

Upon ignition, the igniter should be turned on first and until the sparks generated, turn on the gas. When the gas and the air are mixed to a certain proportion, the fire will be lit up.

Nevertheless, under the circumstance that the exhaust of the gas-type roaster is on, the gas will be exhausted. Therefore, to reach the ignition concentration, there will be filled with gas inside the machine. At this time, there are risks of a gas explosion. Although this type of ignition system is relatively simple in design, it is relatively unsafe, either.

Safer ignition system: pilot burners

Apart from the common and cheaper electric pulse igniter, suppliers tend to apply the safer system, fire pilot burners. It also relies on the sparks generated by the electric system to light up the gas; however, the difference is that it utilises the sparks to light up the pilot burners and let the pilot burners to ignite the gas burner.

The gas concentration is higher at the opening of the burner, so it will mix air at the burner where the pipe diameter is smaller and the flame is also smaller than it of a cigarette lighter.

The flame sensor next to the burner is the safety system designed to detect the temperature. If the temperature is too low, the pilot valve will shut down the gas; if the sensor detects the temperature rises, the burner will be lit up and the valve will open to feed the gas to pilot burner.

This kind of safety system can solve the fundamental issues of high concentration of gas and avoid the electronic igniter failing to light up the gas and cause a gas explosion.

Safety system

The manufacturers of the roasters who pay more attention to the safety of the gas application will install a safety ignition system for the gas-type roasters. The common function is the active intervention system. When it goes over the set temperature, the power supply goes wrong and the flame extinguishes, the system will automatically shut down the gas valve and even linked to the alarm to force start the exhaust system to avoid the negligence of human operation.

Incomplete combustion

Here are three common causes:

  • Gas and air do not mix sufficiently.
  • Excessive gas or oxygen
  • Exhaust gas cannot be discharged properly

Gas combustion is an oxidation reaction that requires sufficient oxygen supply and the environment with a certain temperature to proceed smoothly. If the conditions are not met, a product (such as carbon monoxide) will be produced during the carbon-oxygen reaction, which is commonly known as incomplete combustion.

Therefore, when using a gas-type roaster, in order to ensure the smooth combustion of the gas and not generate carbon monoxide, it is necessary to pay great attention to the ventilation and even the pumping and exhausting system design.

 

Use Electric Heating Roaster, Say Goodbye to Gas Issue

Safety

Safety is the biggest advantage of using an electric heating device. We don’t need to worry about the risks of operating open fire and enable the users to operate the machine with ease. Even the beginners can get in hand easily.

Stability

A gas burner requires oxygen in a certain velocity; otherwise, it may cause the instability of fire source temperature. The biggest advantage of using an electric heating system is that it does not need oxygen. As a result, we don’t need to pay extra attention to the ventilation issue. As long as the corresponding voltage is correct, it does not have limits on the application. In addition, compared to the gas-type roaster, the desired temperature is also much easier to be maintained. Therefore, the application is relatively simple. If the exhaust facility is arranged properly, it will not affect the surrounding environment and the location is without any restrictions.

Space

The structure of an electric heating device is more precise than gas-type roaster and the overall structure design is also more flexible. Thus, the electric heating roaster can be small in size which saves a lot of space. It only takes a small table-sized space.

Rubasse Roaster

The pure electric heating roaster eliminating the need for gas with the independent overheating prevention system will automatically cut off the power supply when it exceeds 260 degrees. The safety of the roasting environment is 100% guaranteed.

If you are a safety-conscious player or roaster who would like to roast wholeheartedly and enjoy the highest quality coffee, you should choose the roasting environment without any risks or concerns. Then, you can make your roast a masterpiece with ease. Choosing electric heating roaster will be the most secure and worthwhile choice.