User Comparison of Instrinsic Safety with Other Hazardous Area Protection Methods

Natick, Massachusetts - A report from Venture Development Corporation (VDC) titled "European and North American Markets for Intrinsically Safe Equipment" examines use of intrinsically safe solutions versus other methods of hazardous environment protection and the motivation for the adoption of intrinsic safety.

Intrinsic safety is a method used to prevent equipment from causing fires and explosions in areas with hazardous atmospheres, such as explosive gas-air mixtures. Equipment and wiring is intrinsically safe if it is incapable of releasing sufficient electrical or thermal energy to cause ignition of a hazardous atmosphere in its most ignitable concentration. Equipment going into hazardous areas for intrinsically safe applications is classified as either simple or non-simple devices.

- Simple devices have limitations on voltages, currents, and energy. These include products such as switches, thermocouples, RTDs, non-inductive potentiometers, and resistors.

- Non-simple devices which include field transmitters, solenoid valves, and many other types of equipment, can create and store energy levels high enough to create an explosion, if not limited. For these applications, the devices have safety limits on the amount of inductance, capacitance, and temperature operating levels. Field wiring to these devices is through intrinsic safety barriers (which are located outside the hazardous region). The barriers limit the voltage and current levels to the devices below those that could cause an explosion.

Both simple and non-simple devices are connected through intrinsic safety barriers. Simple devices connected to an approved intrinsic safety barrier do not have to be approved as being intrinsically safe. Certification for the design and installation of systems with non-simple devices is required. Alternative Methods Used in Hazardous Environment Protection

During this market study, VDC conducted interviews, and a Web-based survey with user designers and specifiers of hazardous environment protection systems in Europe, and North America, including personnel at consulting engineering/construction firms, end users, OEMs, and systems integrators. We found that most users are using multiple methods of hazardous environment protection (see methods below). One method alone may not be sufficient or suitable for all situations and installations because of specifications and regulatory issues. However, most users prefer one method to the others. We found that for European operations, the greatest share of protection is via the use of intrinsic safety. In contrast for North American operations, much greater use is made of explosion proof methods.

Ranking of Alternative Hazardous Environment Protection Methods to Intrinsically Safe Solutions (Based on Users in Survey Applying Methods)


1. Explosion Proof/Flame Proof

2. Pressurization/Purging of Units

3. Encapsulation of Equipment

4. Non-Incendive Equipment*

5. Fiber Optics in Place of Wire

6. Increased Safety Measures**

* - This type equipment is incapable under normal conditions of causing ignition of flammable gas or vapor-in-air mixtures due to arcing or thermal effects. Use of this type equipment is limited to areas where there is low probability of an explosive-gas mixture occurrence, and if it does occur, will exist for only a short period of time.

** - These are methods used to reduce the probability of excessive heat, arcs, or sparks occurring on the internal or external surface of equipment in normal operation. This includes methods such as de-rating of current through terminals, giving enclosures high ingress protection, enhancing insulation values, and increasing creepage clearance distances.

Explosion proofing seals the equipment in large, heavy enclosures with the interface wiring sealed in heavy conduit and armored cables. These are designed to contain the explosion should one occur. These enclosures add to the cost of this method. In addition the enclosures must be maintained, and rigid procedures adhered to when conducting modifications and maintenance on the enclosed equipment. Maintenance of the equipment while in operation is impossible with this method. How users choose hazardous environment protection methods

Users were questioned about what considerations are most important to them in choosing the method of hazardous environment protection. By far the most cited reason is they choose that which is the standard practice locally in their industry. Important reasons for this include:

- Ready availability of trained personnel capable of installing and supporting the equipment when it has local standard practice usage.

- The equipment also is likely to be more readily available when it has local standard practice usage.

These are hindrances to expanded application of intrinsic safety into regions and industries where usage is not well established. VDC found this attitude to be most prevalent for replacement purchases, and minor facility modifications, and less so for new facilities and major modifications.

Cost was identified by significantly fewer of the users as a consideration in their selection. However, when asked what could motivate them to switch to use of intrinsic safety, reduced cost was most identified (by 47% of the respondents), and more so than requiring that the method become a standard practice in their industry (cited by 35%). Perceived cost of intrinsic safety solutions

Users were asked their perception of intrinsic safety solution cost versus other methods. About 80% stated opinions, and these are summarized below. It is interesting that the majority of the others, who could not give general answers regarding the relative cost of intrinsic safety methods and alternative protection methods, did feel that this method is less expensive than explosion proof solutions.

User Perceptions of Intrinsic Safety Solution Costs for Hazardous Area Protection Versus Alternative Methods (Percent of User Respondents Overall)

Intrinsic Safety Costs Less (Total: 50%):

- Less Expensive: 29%

- Less Expensive When Cost of Maintenance is Included: 11%

- Less Expensive When Cost of Installation is Included- 10%

Equal in cost: 17%

Intrinsic Safety is More Expensive: 33%

It is seen above that half of the users who answered regard intrinsic safety solutions as being less expensive, if installation and maintenance costs are considered. With intrinsic safety, it is possible to design for "hot swap" capability (the ability to replace failed products while maintaining operation of others). This is a highly desirable feature.

One-third of the respondents regard intrinsic safety as being more expensive. The intrinsic safety barriers in particular are seen as adding cost to this solution. These also are perceived by some as adding complexity in terms of troubleshooting. Also, some cited ever-changing regulations on installation of intrinsic safety solutions as adding significant cost and time in gaining approvals.

Again based on the survey data, it appears much more likely that users will switch to intrinsic safety in the construction of new facilities, and in major updating projects in existing facilities, rather than for replacements and minor projects, where the perceived benefits of switching are less. A more careful analysis of lifecycle costs, and of state-of-the art industry practices will likely be undertaken for new facilities, and major updating projects.

A case can also be made that significant penetration is possible into industries/applications and geographic regions where other hazardous environment protection methods are used, once a critical mass of relevant users adopt intrinsic safety methods, and where a strong effort is made to educate and support the application and use of intrinsic safety. About the study

The VDC study "European and North American Markets For Intrinsically Safe Equipment" provides markets size, segmentation, and forecasts for intrinsically safe distributed/remote I/O, intrinsic safety barriers, and field instruments used in intrinsically safe applications. Market segmentation and forecasts are provided for Europe and North America, by consuming industries, and by intrinsically safe networks/buses. Market segmentations for the base year are provided for the hazardous environment classifications where the equipment is used, and channels of distribution for the products.

The study includes results of an extensive investigation throughout Europe and North America into user needs and perspectives regarding intrinsically safe products. Included are findings relative to usage of various alternative means of hazardous environment protection, expected trends in hazardous region classifications, in methods of I/O implementation for intrinsic safety applications, and in methods of purchase of these products (as components or as part of intrinsically safe systems). Key product and vendor selection criteria are identified.

Discussion is provided on certification standards, approval procedures and categorization systems for the application of intrinsic safety methods in Europe and North America. An assessment is made of the efforts to harmonize the various standards, approval procedures and marking systems that exist both inside Europe and throughout the world. The impact of these efforts on product designs and future competition is discussed.

An analysis was conducted on competitors currently in the market and the likelihood of new entrants. Partnerships and alliances are examined, along with the impact of new technologies. Vendor market shares are provided for the products, with rankings of the leading suppliers in the major consuming industries, separately for Europe and North America.

The study provides strategies and recommendations on how vendors in each product category can enhance their market positions on a global scale. These cover product offerings, product characteristics and features, targeting consuming industries and regional markets, meeting safety classification needs, channels of distribution, promotion, pricing, buyer education, service, alliances, mergers and acquisitions, and other success factors.

Venture Development Corporation is a technology research and management consulting firm serving the worldwide electronics industry. The report is available at

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