On Thursday 14 April, the branch had the privilege of hosting Gary Friend from Extech Safety Systems. Gary shared a very informative presentation on Intrinsic Safety applications comprised of the following topics:
1. Surge protection in IS Loops: SANS 60079-25 is to be consulted for the specification on surge protection in hazardous zones. One of the important specifications highlighted was: “If part of an IS circuit is installed in Zone 0 in such a way that there is a risk of developing hazardous or damaging potential differences within Zone 0, a surge protection device shall be installed. Surge protection is required between each conductor of the cable including the screen and the structure, where the conductor is not already bonded to the structure. The surge protection device shall be installed outside but as near to the boundary of Zone 0 as practical, preferably within 1 metre.” It is also important to note that surge protection is needed in the following cases: When the instrument is installed 100 m from the isolator/control card in a horizontal position, or 10 m from the isolator/control card in a vertical position.
2. Cables through IS trunking: The rule of thumb is that non-IS cables should not be run through IS trunking, but be mechanically protected from IS cables. Thus IS cables and non-IS cables should run on separate trunking.
3. Cable length in IS loops: The capacitance of the cable will dictate the allowable length of the cable in an IS area. It is important to get the capacitance (pf/m) from the cable manufacturer in order to calculate the capacitance value of the length of cable. Gary mentioned that in certain cases where cables were long and did not meet the capacitance value allowable in an IS area that the area classification was reviewed, and in some cases if found to be over specified, was re-specified.
4. IS in SIL loops: It is important to know that the whole loop needs to be assessed to get a SIL rating and not just a single element. Also note that the lowest SIL rated element in a loop will dictate the maximum SIL value of the loop.
5. Mobile devices: Gary shared a list of Ex rated mobile devices currently in the market that are permissible for use in IS areas. This technology will most certainly improve the communication ability for personnel working in hazardous locations. However, he did mention that careful consideration should be given before utilising in certain specialised IS areas.
Thursday 26 May will see the annual branch Golf Day at Walker Park, Evander with over 20 local manufacturers and suppliers coming out to support us. We are grateful to the SAIMC Patron Members and local businesses for getting behind this event. They have been very supportive of the Secunda Golf Day, which is mainly about having fun and “It’s a bit of a get together”. The day will include a free meal and a prize for all participating players. Honeywell, the 2015 trophy winners, will have to show a lot of irons and balls in order to defend their title at this year’s event. May the course be with you.
All C&I related individuals are welcome to attend our Technology Evenings in 2016, the planned dates are as follows: 2 June, 7-July, 4 August, 1 September, 6 October and 3 November.
All presentations will earn CPD points for ECSA registered persons and enquiries can be directed to Johan Maritz, [email protected], 082 856 3865.
| Tel: | +27 11 312 2445 |
| Email: | [email protected] |
| www: | www.saimc.co.za |
| Articles: | More information and articles about SAIMC |
© Technews Publishing (Pty) Ltd | All Rights Reserved
printer friendly version