ISA TR12.2 : 1995
Current
The latest, up-to-date edition.
INTRINSICALLY SAFE SYSTEM ASSESSMENT USING THE ENTITY CONCEPT
Hardcopy
English
01-01-1995
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1 Introduction
2 The intrinsic safety protection technique
3 Intrinsically safe systems
4 Intrinsically safe system control drawings
5 Entity concept
6 Entity parameters
7 Entity concept control drawings
8 Assessing the intrinsic safety of simple loops
9 Loop operation considerations
10 Special considerations for multi-channel associated
apparatus loops
11 Assessing the intrinsic safety of complex loops
12 Intrinsically safe apparatus that adds energy to the
loop
13 Considerations for intrinsically safe bus systems
14 Conclusion
15 References
Figures
1 - Example of a typical control drawing
2 - Control drawing for an intrinsically safe apparatus
examined under the entity concept
3 - Control drawing for an associated apparatus examined
under the entity concept
4 - Two-wire loop with neither conductor connected to
ground using two single-channel associated apparatus
5 - Two-wire loop with neither conductor connected to
ground using one dual-channel associated apparatus
6 - Control drawing for two-channel associated apparatus
with Vt and lt parameters
7 - Complex loop with two intrinsically safe apparatus and
three two-channel associated apparatus
8 - Control drawing for three two-channel associated
apparatus with Vt and lt
9 - Control drawing for intrinsically safe apparatus with
multiple circuits
10 - Control drawing for intrinsically safe apparatus
11 - Control drawing for hand-held communicator
12 - Typical intrinsically safe bus configuration
Gives information and examples for assessing intrinsic safety of a wide variety of control loops using the control drawings and the entity concept.
| Committee |
SP12
|
| DocumentType |
Standard
|
| Pages |
27
|
| PublisherName |
International Society of Automation
|
| Status |
Current
|
| C22.1-15 PACKAGE | Consists of C22.1-15, Canadian electrical code, part I (23rd edition), safety standard for electrical installations; C22.1HB-15, Canadian electrical code handbook - an explanation of rules of the Canadian electrical code, part I and the 2015 Electrical quick reference |
| C22.1HB-18 | Canadian Electrical Code Handbook - An Explanation of the Rules of the Canadian Electrical Code, Part I |
| CSA C22.4 No. 1 : 2009(R2018) | OBJECTIVE-BASED INDUSTRIAL ELECTRICAL CODE |
| CSA C22.4 PACKAGE : 2009 | CONSISTS OF C22.4 NO. 1-09, OBJECTIVE-BASED INDUSTRIAL ELECTRICAL CODE AND C22.4 NO. 2-09, OBJECTIVE-BASED INDUSTRIAL ELECTRICAL CODE - SAFETY MANAGEMENT SYSTEM REQUIREMENTS |
| ISA S12.1 : 1991 | DEFINITIONS AND INFORMATION PERTAINING TO ELECTRICAL INSTRUMENTS IN HAZARDOUS (CLASSIFIED) LOCATIONS |
| NFPA 70 : 2017 | NATIONAL ELECTRICAL CODE |
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