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Gas Detection

Published: 10th Jun 2010 in OSA Magazine

Gas detectors for the Chinese market

The certification process for gas detection equipment can be complicated in China. Gas detection manufacturers from other major trading blocks around the world will find that exporting products to the Chinese market doesn’t follow a similar route to those for European or North American approval, for example. Differences in national standards, and a stringent approval route makes Chinese approval for gas detection products confusing and time-consuming, but not without its economic advantages.

To help clarify the issue, Sira Certification, the UK’s leading provider of ‘Ex’ approvals (and part of CSA International), outlines the certification process that manufacturers of gas detection equipment must follow to export their products to the Chinese market.

The main requirements

There are three stages to achieving sufficient Chinese Approval for gas detection equipment, all of which require some form of certification from recognised Chinese Testing Agencies. The extent of approval will obviously depend on the intended use of your gas detection equipment, but what follows is a typical guide that the majority of gas detection manufacturers will need to undertake to sell products in China.

Stage 1 - Chinese Ex Certification by a National Testing Agency

MA approval for group I (mining)

Products placed on the Chinese market must conform to the relevant certification scheme implemented by the Chinese government. If the gas detection equipment is to be used in mining applications, MA Approval is required as a mandatory conformity requirement.

Luckily, manufacturers who already hold Sira ATEX Group I certification can use their certificates and reports as a basis for applying for MA Approval. The manufacturer would need to apply to the Chinese certification body (Sira can provide details of this agency on request), sending copies of their ATEX certificates and reports. The testing agency accepts Sira ATEX certificate reports in all or in part, depending upon the age and scope of the certificate. 

Some Chinese Testing Agencies have agreements in place with European notified bodies, with the aim to accept their certifications as part of the process to achieving MA Approval. Sira, for example, has an agreement with the Chinese body CCST, which enables Sira to provide a report to CCST to help with the certification process and reduce certification timescales. 

Local agents with an in-depth knowledge of the certification process can also be utilised to help push certification through (contact information available on request).   

Other anti-explosion approvals can be considered by Chinese National Testing Agencies, although the extent of acceptability, and therefore the amount of additional work needed to comply with MA requirements, may vary depending on the source, age and scope of the approval. 

Obtaining MA Certification from scratch can take up to six months, although with ATEX Group I certification from a notified body with reciprocal agreements with Chinese test agencies (and/or with the help of local agents), the process can be reduced to around three months. 

An important point to note is that, as with many other international certification schemes, factory audits will be necessary for the Chinese Test Agency. These are typically conducted every three years and can be expensive and time consuming. Alternatively, batch inspection can be carried out provided the manufacturer can identify the end customers who will be receiving the products. The inspection is carried out in China, but some facilities to complete the inspection work may be needed.

China Ex Approval
(for Group II non-mining)

China Ex approval is a voluntary requirement with no factory inspection, although can provide a marketing advantage when it comes to placing your gas detection equipment on the market.

Many Chinese customers want suppliers to have such a certificate as well as some form of anti-explosion certification from a foreign certification body, and in many cases, China Ex approval is seen as a pre-requisite in an end-user’s decision making process when they come to source gas detection products. China Ex approval can take two to three months to complete, using a Chinese Testing Agency.

Testing is carried out against the GB series standards, which are based on the IEC 60079 series, but clients with Sira certificates can use their test reports as a basis for proving compliance. Sira has agreements with NEPSI and CQST that enable acceptance of test data.

Stage 2 - Chinese Pattern Approval Operated by the State General Administration of the People’s Republic of China, for Quality Supervision, Inspection and Quarantine (AQSIQ)

This requirement is mainly related with metrology according to the Law of Metrology of China. The pattern approval system includes product listings for 75 categories of measuring instruments, in which the gas detection apparatus for CO2, H2S, CO, CO2, NOx, H2, CH4 are involved.

For the pattern approval, the manufacturer must forward an application form to AQSIQ. The officer at AQSIQ will then assign a national level testing lab to conduct a type test based on the Chinese approval standard. 

Satisfactory testing of the equipment will then allow AQSIQ to issue a type of approval certificate. No factory inspections are required for this aspect of approval work, however, timescales for certification alone can be in the region of five to six months before compliance is confirmed.

Stage 3 -Type Approval for Fire Safety, Operated by the China Certification Center for Fire Products Ministry of Public Security (CCCF)

This is a mandatory certification system for fire protection products. For the?certificate of type approval, the manufacturer must present an application to CCCF in Beijing. CCCF will then organise an assessment team to conduct an on-site factory audit. 

If the audit result is satisfactory, a sampling of related products will be made by the team, and these samples will be forwarded to an assigned national level testing lab to conduct a type test based on relevant Chinese approval standards.

Finally, CCCF will issue a type approval certificate based on the type test report and site audit report. The certificate is normally valid for three
to fives years (depending on the complexity of type test), upon which time the certification exercise and audit will be conducted again. 

The duration of assessments and certification/testing time typically falls within five to seven months. 

It’s important to note that  both of the type approvals for fire safety and metrology (stages 2 and 3) are mainly based on the same standard (GB15332), which is similar to IEC 61179, however, for metrology approval there is also a series of verification regulations which concern metrological accuracy, action-time, climate (high temp, low temp, humidity), vibration and EMC testing.

Summary

As has been shown, exporting gas detection equipment to China is a unique process from a certification perceptive, and is often tricky and time-consuming to complete (timescales can be reduced, however, if manufacturers use European bodies that have agreements in place with Chinese Testing Agencies, as this helps reduce the amount of approval work required, and therefore time and price).  However, despite these initial drawbacks, the experience of other Ex manufacturers already selling equipment on the Chinese market has shown that there is a financial advantage of exporting to one of the world’s fastest expanding economies, especially one with a booming mining industry and a now more conscientious approach to safety in potentially explosive environments.

Author Details:

Sira Certification
Sira is the UK’s leading notified body for Ex certification, specialising in ATEX, IECEx and international approvals. As part of CSA International, Sira provides compliance services helping manufacturers export products to international markets around the world.  Sira has a range of agreements with Chinese approval bodies which enable a more streamlined and timely approval route, and can carry out the performance tests and functional safety verification (including software) which may be required for Chinese approvals. For more information about Sira, or global market access, please contact us:

Tel: +44 (0) 124 670 900
Email: info@siracertificationcom
Web : www.siracertification.com

In China, before going down the mine shaft, necessary equipment includes a self-relief package (oxygen supplier), a mine lamp, hard hat and uniform.

A gas detector is also a necessity - at least one gas detector for each group. Meanwhile, at the mine site, there are stationary gas detecting devices which, according to safety regulations, are located at hazardous areas and mounted on machines. 

From history records, gas is the premier cause of disastrous accidents in the Chinese coal mining industry. Since 2001, the Chinese government has taken strict measures to improve safety technology and to control gas accidents, investing 5.9 billion RMB in state-owned coal mines to assist in improvements. By the end of 2004, state-owned coal mines installed 552 sets of safety monitoring systems with 35,064 detectors of gas and CO, an electricity on-off mechanism. In addition, 45 hyper-monitored mine companies were equipped with 392 sets of monitoring systems, and high-gas mines were all equipped with such systems.   

Although the figures of recent years are not available under present regulations, the coal mines without safety monitoring systems will not be granted licenses. Apparently, gas detection plays a very important part in this progressive project.

Two policy makers, the State Administration of Work Safety and the State Administration of Coal Mine Safety, issued «??????»(Coal Mine Safety Regulations), in which it specified guidelines for gas monitoring and detection, their requirements for the distribution and arrangement of detectors and sensors, and for relevant gas inspection mechanisms. With regard to safety issues, the gases (CH4), CO2 and CO are the major focus of gas detection underground. Based on emission volumes of the gases, coal mines are classified into low-gas, high-gas, and gas outburst mines. Different mine types will require different arrangements of detectors, different limit values and different reactions (see table 1), but safety concerns are not loosened due to their classification. For a low-gas mine, methane sensors must be mounted at the excavating site; for high-gas and gas outburst mines, portable methane alarms are required to be added at the working area, while methane sensors must be installed in the return airway. The installed methane detecting devices connect with safety monitoring systems, or electricity cut-off mechanisms. When the gas density exceeds limits, these detectors or sensors instigate alarming, electricity cut-off and security reactions. 

Under safety regulations, portable gas detectors are strictly required for underground workers and excavating machines. For personal protection, the mine principal, technical principal, explosives expert, chief of excavating area, chief of venting area, engineer, foreman and electrician must all be equipped with portable gas detectors. For gas inspection, the gas inspector must carry a methane detector of the interferometer type, while a safety inspector must take either this, or a methane alarming detector. In 2003, a convenient gas detector - a kind of micro-processor placed in the battery of a mine lamp - was put into use for miners. Here, when gas density gets to alarm point, an acousto-optic alarm is triggered, and doesn’t stop until the gas density drops back to below the alarm point. Normally, at least one person must be equipped with this gas detector lamp when a work team goes down the shaft. For arrangement of gas detecting points, the excavating site, electrical equipment area and all working sites must be gas-detecting regions. Additionally, all excavating machines must be mounted with methane electricity cut-off mechanisms or portable methane alarming detectors. Take a diesel vehicle, for example: when gas density exceeds 0.5%, the detector alarm sounds, and it must be switched off immediately for safety concerns.    

Despite stationary gas detecting devices at hazardous areas, trained personnel - gas inspectors - should check gas density periodically with portable gas detectors (see table 2). An interferometer detector is a designated methane checking device for professional gas inspectors, because it is a comparatively accurate meter in the gas detection, but, in practice, it’s not very convenient for the purpose. According to regulations, gas checks and records must be must be accurately recorded in files and shown on a warning board at the working site. When gas density increases beyond safe limits, gas inspectors have the right to stop the on-site work and assign workers to a safe place. For those coal mines where it’s possible to get a self-ignite condition, detection on CO and air temperature must be checked periodically and recorded. 

As mentioned above, gas-caused mishaps play the biggest part in Chinese coal mine accidents. From fault analysis, poor discipline on gas detection is what mostly undermines safety monitoring systems and caused fatal disasters.
Some mine owners’ precautions are casual, and lack strict training programmes for employees. They don’t install stationary sensors and detectors for gas detection, nor do they have a well-formed gas inspection system or the required portable gas detectors for people going underground. Based on statistics, small coal mines can be notorious for slack management and inadequate equipment, bringing discredit to this industry. But Chinese authorities have taken effective measures to sort out these potential safety concerns, last year integrating the small coal mines in Shanxi province as an example. Besides progress in regulation and management, China has also strengthened the supervision of equipment in terms of safety and performance.

The Chinese national standard GB12358 is a general technical requirement on detectors of flammable gas, toxic gas and Oxygen. However, according to application conditions, the gas detector may be subject to different certification against specified standards and regulations. Generally, in China, gas detectors applied in coal mines covered by MA certification, in a refinery or chemical factory, for example, should be capped with China Ex. With regard to fire safety, CCCF Approval is required - this and MA certification is mandatory. Although China Ex is voluntary certification, Chinese customers will require explosion-proof approval from supplier, but, practically, the gas detector capped with ATEX or FM or another accredited body would be acceptable.

Among safety concerns, coal mine safety is a high priority for the Chinese government. The supervising authority, China Mining Products Safety Approval and Certification Center (MA Center), has established the MA certification and surveillance system, and the management is doing the best to improve and perfect the mechanism. There are now 19 designated test centers in charge of the relevant inspection of mining equipment, from big-size system to button battery.
We call these should-be-certified products Controlled Equipments, and each designated test centre has certain inspection facilities covering specific elements of these. For gas detecting devices, there are presently four test centres which can do the inspections against MA standards and regulations, but each of them covers particular areas.

As one sort of electrical equipments, gas detecting devices, under MA certification, should be tested not only over explosion-proof characters of themselves but over its performance. In the case of explosion-proof, gas detectors should comply with China national standard GB 3836.1 (Equivalent with IEC 60079-0) the general requirements on electrical apparatus for explosive gas atmospheres; Specifically, GB 3836.2 and/or GB 3836.4 will be added in test instruction for specified gas detectors in terms of their explosion-proof type. GB 3836.2 is equivalent with IEC 60079-1, on flameproof enclosures, while GB 3836.4 is equivalent with IEC 60079-11, on intrinsic safety. For stationary gas detecting equipments, located at hazardous atmosphere underground, some are explosion-proof type ‘di’ and co-work with electricity cut-off/re-on mechanism and safety monitoring system. The portable gas detectors on body or carrying machines are mostly intrinsic safety. The table, left, lists some kinds of gas detectors widely used for personal protection and safety systems in coal mines (see table 3).

According to these standards, certified products should bear approval marks on their nameplates or packages. Explosion-proof approval mark is ‘Ex’ coal mine approval mark is ‘MA’, and, as to metrological instruments, they should have pattern approval ‘CMC’ So, potential users should, based on application requirements, check certain approvals on gas detecting apparatus before purchasing it. Additionally, the regulations standardise the coding methodology, and professionals
may read basic information from the type code. ?

References:

  1. «??????»(Coal Mine Safety Regulations)
  2. «??????»(Mine Safety Metrology)
  3. www.mkaq.org
  4. www.aqbz.org

Many thanks to those engineers and relevant people who work in certification bodies or mine industry, and provided helps to complete this article. 
 

Published: 10th Jun 2010 in OSA Magazine

Author


Adam Garner and Bill Chen


Sira Certification

Sira is the UK’s leading notified body for Ex certification, specialising in ATEX, IECEx and international approvals. As part of CSA International, Sira provides compliance services helping manufacturers export products to international markets around the world.  Sira has a range of agreements with Chinese approval bodies which enable a more streamlined and timely approval route, and can carry out the performance tests and functional safety verification (including software) which may be required for Chinese approvals. For more information about Sira, or global market access, please contact us: 

Tel: +44 (0) 124 670 900

Email: info@siracertificationcom

Web: http://www.siracertification.com

CHEN Ming (Bill CHEN): is a China product certification consultant, works at YTC and assists foreign manufacturers to get through China certification. 

YTC: Yang’s Technology Consulting, a professional solution provider for China product certification. 

Email: bill-chen@cnytc.com.

Web:  http://www.cnytc.com


Adam Garner and Bill Chen

Website:
http://www.siracertification.com

Email:
info@siracertificationcom

Phone:
+44 (0) 124 670 900

info@siracertificationcom
http://www.siracertification.com
+44 (0) 124 670 900

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