Offshore Platform Leg Inspection Wolf Safety

Transcription

1 Hazardous Area 1 st August Page 1 of 10

2 Contents 1 Summary Temporary Luminaire Configuration Rope Access Compatibility Alternative illumination solution Appendix Page 2 of 10

3 1 Summary Wolf has been asked to propose a temporary lighting solution to Shell for illuminating the inside of an offshore platform leg to aid in inspection and maintenance. This application requires a series of lights to be lowered down on ropes inside the platform leg, a 40 metre drop from leg top to base, where the lights must be spaced at even intervals to give a basic level of uniform illumination. The specification for the application is that a quantity of eight luminaires should be used to generate adequate light to illuminate the platform leg. Additionally, due to the application being on an offshore platform, and the environment of use being a steel constructed confined space, the lighting must be ATEX zone 1 compliant and powered from the platform 254 volt lighting supply, but with the lighting run in-situ at 24 volts. The new Wolf Linkex LED Temporary Luminaire offers the ideal, cost effective solution for this application due to the following benefits:- The Linkex LED temporary Luminaire emits a wide angle ambient light, able to offer effective illumination for general work tasks. The Linkex LED has a zone 1 ATEX certificate for use in potentially explosive atmospheres. The Linkex LED has a robust construction, perfectly suited to this type of temporary lighting application in a harsh environment. The Linkex LED can be supplied in a linkable form, with 24v ATEX sockets fitted, allowing strings of lights to be interconnected. The Linkex LED is available as a Tank Lighting Kit, supplied with ATEX zone 1 transformer with 254v input and capable of running eight 24v Linkex LED lights in two strings of four dependent on exact configuration requirement. The Linkex LED Temporary Luminaire can be supplied with brackets capable of being attached to climbing rope, enabling the lights to be securely lowered into position in the platform leg, as required. Linkex LED 24v lights can effectively be linked in series in a short string, despite the difficulties in using this type of arrangement, because the LED light source is low power and highly efficient (calculated to give a similar light output to existing fluorescent temporary luminaire units but using only 40% of the power). Running strings of lights at extra low voltages can present significant problems with voltage drops, where the Luminaire can end up running at voltages outside of the safe ATEX specified voltage limits; the Linkex LED built-in SOVI monitor safe operation voltage indicator can immediately show whether the Luminaire is running at a correct, safe voltage. Page 3 of 10

4 2 Temporary Luminaire Configuration Running eight Linkex LED Temporary Luminaires from one ATEX Transformer voltage compatability The configuration that Shell is understood to require calls for eight temporary luminaires to be run from one transformer in two strings of linked lights for a distance of 40 metres. This would mean that each of the two strings will have four lights, and that one string, as the worst case, must have 10 metres of cable between each of the four lights, a total of 40 metres of cable to the final light. This requirement is very challenging for three reasons:- 1. When powering electrical equipment at extra low voltages, such as 24 volts as required in this application, voltage drops are very significant over comparatively short cable runs. 2. When running multiple temporary luminaire units in series (electrically running in parallel), where a single length of cable is carrying so much current, voltage drop can be very significant, adding to the drop in voltage as already set out in 1. above, 3. To comply with ATEX legislation and ensure that equipment is used safely, all ATEX equipment must be run at a voltage within the limitations set out in the ATEX certification documentation of the specific equipment being used. This can be very difficult when faced with the voltage drop issues set out in points 1. and 2. above. Recent Wolf Linkex LED Tank Lighting Kit orders have required a similar configuration to that required by Shell for platform legs; these have been thoroughly evaluated before being supplied. Whilst the configuration supplied was slightly different, it was comparable and, if anything, slightly more onerous. Page 4 of 10

5 The configuration tested used an ATEX transformer rated at 230v, and run at this exact input voltage (i.e. 24v output would be correct, as in the situation of a 254v transformer run at 254v) therefore output voltage was nominal 24 volts - powering two strings of four lights, where the first two lights of each string had 20 metre cables and the second two lights of each string had 5 metre cables, a total of 50 metres for each string of lights. In this configuration all lights were verified as running within the specified Linkex LED ATEX certified voltage range of 19 volts to 28 volts. This correct voltage could be easily verified with the SOVI safe operation voltage indicator monitor built into each Linkex LED Temporary Luminaire. A report on the testing of this configuration, confirming voltage levels recorded, is attached in the appendix (see test 2. Page 5 of 10

6 3 Rope Access Compatibility The Linkex LED Temporary Luminaire can be fitted with brackets that accept karabiners, capable of being attached to climbing rope and enabling the lights to be securely lowered into position in the platform leg, as Page 6 of 10

7 required. The brackets can be positioned top and bottom on each Wolf Linkex LED temporary Luminaire for extra security and stability. Page 7 of 10

8 Appropriate measures can also be proposed that would adequately support the cable and reduce excessive strain on the linkable ATEX socket. 3.1 Alternative illumination solution If work tasks are to be carried out requiring greater levels of illumination then the Wolf WF-300 LED Floodlite can be used, again secured to rope and lowered into the platform leg. The power and ATEX transformer solution would need to be reconsidered if this were required. Page 8 of 10

9 4 Appendix LinkEx LED RIG LEG SETUP Design File: Tested By: Andrew Kempton Location: R&D Type: Voltage and Observation Products: 8 x LV LinkExLED lights, 24V 400VA transformer + variac Aim: Establish Voltage of last lamp in a chain for the Rig Enquiry: Test1: Results: With this setup and cable lengths of 20m to the first lamp then 5m between each The Voltage at the last lamp was as follows Input Voltage Voltage at socket of 4 th lamp (Green) (Green) (Green possibly red) Page 9 of 10

10 Test2: Results: With this setup and cable lengths of 20m to the first two lamps, then 5m between the other two,t the Voltage at the last lamp was as follows:- Input Voltage Voltage at socket of 4 th lamp (Green) (Green) (Red) 207 (230 10%) 18.0 (Red) Page 10 of 10