ISA 60079-27

This standard contains the details of apparatus, systemsand installation practice for use with the Fieldbus IntrinsicallySafe Concept (FISCO) for installation and use in Class I, Zones0 and 1 and the Fieldbus Non-Incendive Concept (FNICO) forinstallation and use in Class I, Zone 2. It is based on theconcepts of Manchester encoded, bus powered systems designed inaccordance with IEC 61158-2 which is the physical layer standardfor Fieldbus installations.

The constructional requirements of FISCO and FNICO apparatus andsystems are determined by ANSI/ISA-60079-11 andANSI/ISA-60079-15, except as modified by this standard. Part ofa Fieldbus device may be protected by any of the methods ofexplosion protection listed in ANSI/ISA-60079-0 suitable for theapplication. In these circumstances, the requirements of thisstandard apply only to that part of the apparatus directlyconnected to the intrinsically safe or non-incendive trunk orspurs.

NOTE 1 Certification to the FISCO requirements does not preventapparatus also being certified and marked toANSI/ISA-60079-11 in the conventional manner so that theymay be used in other systems. Some apparatus certified before thisstandard was published but not necessarily complying with theelectrical parameters of this standard may be marked ‘Suitable forFISCO systems’. This apparatus may be accepted in a FISCO system,if the comparison of the electrical parametersU_o, I_o,P_o, with U_i,I_i, P_i, demonstratecompatibility with the remainder of the system, and all the otherrequirements of this standard are met.

NOTE 2 A typical system is illustrated in Clause 10.

NOTE 3 Generally, FNICO systems are intended for use in Zone 2locations. FISCO systems are predominantly intended for use in Zone1 and 2 locations, but may enter Zone 0 locations if specificallypermitted to do so by the Control Drawing.

NOTE 4 This standard uses the IEC designations (Uo,Io, Po etc.) for electrical parameters throughout, however, either the ISA markings, the IEC markings, or both,as shown in Table 12.3, of ANSI/ISA-60079-11 may be used todesignate electrical circuit parameters on the apparatus and in theinstallation documents and control drawing.

NOTE 5 This standard is for apparatus for use in a Class IZone 0, 1 or 2 hazardous (classified) location but the principlescontained may be used for examination of apparatus for use in ClassI, Divisions 1 and 2 as permitted by 501.5 of the NationalElectrical Code ANSI/NFPA 70.

Edition:

06

Published:

01/01/2006

ANSI:

ANSI Approved

Number of Pages:

26

File Size:

1 file , 160 KB