Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China and specializes in explosion-proof certification and coal safety certification application consulting services, offering one-stop explosion-proof technology consulting services.
Division of explosion-proof zones in combustible dust environments -- Shenzhen ZhongNuo Testing Technology Co., Ltd.
In explosion-proof certification, hazardous areas are divided into explosive gas environments and combustible dust environments based on the different states of substances present in the location. According to the duration of presence of hazardous substances in the location, these hazardous areas under two different states are further divided into three zones.
For environments with combustible dust, it is 20, 21, and 22 Zones.
Areas in Zone 20 where flammable dust environments occur continuously or persist for extended periods, typically exceeding 1000 hours per year.
Zone 21 – Areas where combustible dust environments may occur during normal operation, typically 10-1000 hours/year
Zone 22 is not expected to have flammable dust environments during normal operation, nor are there places that occasionally exist for a short period of time. Generally, occurrences are below 10h/y.

Many customers inquire about the difference between obtaining explosion-proof certification and a certificate of conformity for explosion-proof products.
Explosion-proof certification and explosion-proof certificate are two distinct concepts. Once a product undergoes explosion-proof certification, the result is an explosion-proof certificate.
Explosion-proof certification is the process, and the explosion-proof certificate is the result.
So the customer mentioned that the product needs to obtain a explosion-proof certification or an explosion-proof compliance certificate, which means the product must pass the relevant explosion-proof standard tests and meet the standard requirements to obtain the explosion-proof compliance certificate.
Explosion-proof certifications can be categorized into intrinsic safety types, flameproof types, positive pressure types, and encased types, among other explosion-proof protection styles.
ZhongNuo Inspection boasts a team of explosion-proof engineers capable of offering preliminary design services for explosion-proof circuits and structures. We assist companies in compiling the necessary drawings, manuals, and corporate standards required for explosion-proof certification, facilitating their streamlined acquisition of the explosion-proof qualification certificate.
If you require certification in this area, feel free to message us directly!

What is an explosion-proof positive pressure system? What technical requirements are there for obtaining a positive pressure explosion-proof certification for a product?
Positive pressure explosion-proof refers to introducing clean air or inert gas into the interior of the equipment.
Maintain internal equipment pressure above the external explosive environment pressure to isolate explosive mixtures from entering the equipment, thereby achieving explosion-proof performance.
The explosion-proof certification applicable standards are GB/T 3836.1 and GB/T 3836.5.
Primarily assess the equipment's ventilation time, pressure monitoring system, pressure range, blow-off, and alarm functions to meet explosion-proof performance requirements.
Positive pressure type includes three explosion-proof grades: pxb, pyb, and pzc.
Choose the appropriate explosion-proof certification level based on product structure and explosion-proof zones.
ZhongNuo Inspection has been in the explosion-proof industry for many years, well-versed in the requirements of the GB/T 3836 series standards.
We have extensive certification experience in the positive pressure explosion-proof field.
Offer a one-stop technical guidance and consulting service for explosion-proof design and rectification, drawing evaluation, installation guidance, and certification.
Our successful cases include positive pressure ultrasonic shock plates, positive pressure omni-directional antennas, and positive pressure film thickness gauges, etc.
If you have a need for this, feel free to DM us anytime!

How to inquire about explosion-proof certification
Buyers and selectors of explosion-proof electrical equipment always opt for manufacturers or distributors with valid explosion-proof certification.
So, as a consumer, how do users verify the authenticity and validity of the explosion-proof certification?
Currently, there are a dozen or so authorized certification bodies in China that issue explosion-proof certificates.
There is no unified search platform for explosion-proof certificates issued by various certification authorities.
Certifications of explosion-proof compliance issued by various institutions can only be verified on their respective websites.
Of course, every issuing institution can verify the authenticity of certificates by phone.
If the certificate query is genuine, the main parameters and validity period will be displayed below.
If so, of course, it couldn't be found.
It's worth noting that due to each issuing authority manually uploading their certification documents, there is a certain lag.
That is to say, the newly acquired certificate may not yet be searchable on their website.
It's time to directly consult with the shipping agency.
Explosion-proof Certification Application Consultancy Services - Shenzhen Zhongnuo Testing Technology Co., Ltd.