Lighting Systems
From Ukcaving.com wiki
Contents |
LED
LED based lights have virtually replaced Bulb-based systems, at least for new purchases, although many rechargable miners'-type lamps will remain in circulation for some time. Modern LED caving lamps are much lighter-weight, dispense with the need for a heavy waist-mounted battery, and last rather longer, and the very recent ones are at least as bright as the best halogen-rechargable miners' type lamps. The technology is now such that a small, helmet mounted unit, using dry-cells or a small modern rechargeable battery (eg NiMh) can give a good light, with long or very long duration and minimal weight. This is a rapidly evolving field and the LEDs are getting brighter and cheaper with each generation. Battery technology too is advancing rapidly so cavers can benefit from innovation from the mobile phone and laptop computer industries.
The long-duration and convenience of LED-based lights using dry-cells has also to a considerable degree displaced carbide lamps from use in expeditions.
At the time of writing, a number of purpose-made LED units are being marketted for caving with the high-end models including amongs others the Swiss Scurion, a work-of-art in milled aluminium; the Stenlight, or the Speleotechnics Nova. {note - it would be good if some users can do write up on their lights based on experience}
Smaller LED lamps are ideal as a backup to a brighter main light. Petzl and others make a number of neat headlights very suitable as backup lights, the Myo XP and Tika XP models especially so. Either of these units, or equivalents from other makers, are bright enough as main caving lights, are reasonably priced, and reasonably robust within limits, albeit not bombroof like a proper miner's lamp or a purpose-built caving lamp. Small LED torches can also serve as backups, eg those used by SCUBA divers, and can be permanently mounted on the side of the helmet. A backup light for caving does need to be at least somewhat robust, especially if permanently left on the helmet.
Bulb
The traditional caver's lamp consists of a belt-mounted battery pack, connected via a robust cable to a helmet-mounted headset. This might be a lead-acid miner's lamp such as the "Oldham" (based on a 2-cell 4 volt battery), or a more modern unit based on 2, 3 or 4 NiCad (or equivalent) cells. Some of these are designed for mining such as the 6V Spanish unit, or specially for the caving market (eg FX2 and FX5, and the "Kirby" lamp).
The FX2 is a bit dim compared to alternatives and shares with the, much brighter, though heavier and more expensive, FX5 a slightly wobbly wing-nut arrangement for attaching the battery to the lamp and cable (albeit which gives interchangeability). The Kirby is also a pretty good unit, but after heavy use can suffer from damage to the cable where it enters the battery; the cable not being replaceable. The Spanish miner's lamp [author's note - what are these actually called ?] is an excellent unit and perhaps the best commercially available unit of its type, though with the slight irritation that the normal 50mm caver's belay belt will not fit through the belt-loops. A narrower belt must therefore be used. No doubt there are other alternatives. At least some of these, especially those targetted at cavers, now come in LED versions, or hybrid with LEDs combined with a halogen bulb.
Many cavers have made their own units using commercial headsets and assembling batteries from NiCad or NiMh D-cells or F-Cells in a suitable case (usually 4 giving nominally 6 Volts). Properly made, these are very similar in performance and use to FX5, Kirby, or the Spanish lamp.
The lead-acid Oldham miner's lamp and its brothers can't really be recommended these days as it needs diligent charging if it to have a reasonable service-life, tends to get ruined by water ingress if swimming, and is very prone to acid leakage which is highly damaging to nylon SRT ropes and harnesses so a bit of a worry on SRT trips!
The distinctive stainless-steel cases of Nife lamps are still occasionally seen, though most if not all are now only cases for more modern sealed cells. Proper Nife cells are now really only of historic interest though they were were very robust and well-regarded, but were prone to leaking highly-caustic Potassium Hydroxide electrolyte which could cause nasty burns and damage equipment - especially polyester harnesses and ropes (thought polyester ropes are now less common).
Halogen bulbs are much brighter than equivalent non-halogen bulbs and well worth installing for the modest extra cost involved.
Although LED systems are rapidly gaining popularity, the belt-mounted miner's type lamp with a halogen bulb still gives a good light, at least with the 6V versions, albeit with shorter burn-time and much greater weight. However the incandescent bulb's days are probably numbered given the continuing advances in LED lighting systems and battery technology once those in service reach the end of their useful lives.
Carbide
Carbide / Acetylene lamps were once quite a popular choice of caving lamp, and still (just about) have a place for expedition caving where recharging batteries may be impractical. Calcium Carbide(CaC2) gives off acetylene gas (C2H2) when water is added, producing calcium Hydroxide (lime, Ca(OH)2) as waste-product. The acetylene is then burnt to give a bright wide-beamed light. Back in the even-older days carbide lamps were used on bicycles and even on cars. The traditional UK caving lamp was the "Premier" cap-lamp or "Stinky". It was originally made for miners rather than cavers: for metal mines not coal mines obviously! The gas generator and burner is a single unit which mounts on the helmet. It lasted perhaps a couple of hours on fill of carbide. The light was quite good if fitted with a larger-sized reflector, but was very hard to light once the flint igniter got wet, and barely reliable at the best of times. Most were relegated to the mantelpiece when electric miners' lamps became available / affordable.
Though some still have fond memories of the old Premier stinky, others (including the author) regard them as unreliable and an infernal nuisance. A much more practical proposition is the "expedition" carbide, with a separate generator hung from a belt, linked to a burner and reflector on the helmet via a pipe. These give a terrific light, and anything between 5 and 10 hours on a fill of carbide (given several fills of water). Most have a piezo-electric ignition system which is vastly superior to the flint on the old stinky. They still require a fair bit of skill and perseverance to master. Normally a small electric head torch is carried as a back up for when the flame goes out in a waterfall, or at highly-inconvenient moment half-way up a pitch. A number of different generator units have been available, the most popular is perhaps the Fisma, subsequently marketed by Petzl. This is a robust, agricultural-looking item, which works well once mastered. Petzl themselves produced the Ariane, a modern-looking plastic (though still robust) unit, which some users like, but is not rated at all by other users. A terrific more modern unit, was a self-pressuring work of art in stainless steel. Because it is self-pressuring, gas isn't wasted by bubbling away through the water reservoir as with other units. Once adjusted properly, you can get a great deal longer out of one fill of carbide. However it does tend to go berserk if too much water is added!
Various headsets can be chosen, Petzl being probably the most popular, though not necessarily the best. Petzl produce a burner-only model, and a combined burner with electric back-up - both with piezo electric ignition. The electric backup is frankly a bit ropey, so a separate small headlight (eg an LED unit, such as one of Petzl's) is a better option. The peizo ignition is really excellent and very reliable for a long time. The reflector is too small so wastes a lot of the potential light compared to some of the more agricultural wok-like reflectors on some other units which occasionally seen. Unfortunately none of the others has anything like as good a lighter as Petzl's piezo system. Perhaps some hybrid could be contrived with the Petzl lighter but a bigger reflector?
Most users make various small modifications to their lamps: popular tweaks include substituting a nylon mesh (ball-type) pan-scourer for the supplied filter, fixing on the hose with proper jubilee clips, etc.
An essential adjunct to the carbide lamp is the "pig" for carrying carbide, consisting of a length of (ideally Land-Rover) inner-tube, which can be sealed up each end with further loops of inner tube twisted over. A further loop is used to divide the pig in the middle so that spend carbide can be carried out of the cave in one half, with fresh carbide in the other. Alternatively a 2nd pig can be taken to carry the dregs out which simplifies things and avoids risk of dampness contaminating the fresh carbide.
It shouldn't need to be stated here, but carbide dregs (Ca(OH)2) should always be carried out of the cave and not dumped. As well as being unsightly, it is toxic to cave life, smelly, and generally unpleasant and unnecessary. Sadly in less enlightened times, carbide got a bad reputation due to irresponsible people dumping it in caves, and hence is banned from many systems. A trip to any of the classic European systems will show the worst excesses of dumping, with quite literally tonnes of carbide dumped in the Berger for example.
Even for expedition caving, various long-duration LED-based lamps are taking over, though they do not give anywhere near as good a light as an expedition carbide, nor provide the warmth much less the companionship if a hissing lamp. However they do require far less faff and are more reliable. Sufficient spare (dry-cell or rechargeable) batteries can be carried to give enough duration for any conceivable trip with far less weight and hassle than the equivalent amount of carbide
Recently, calcium carbide has become rather more difficult to get, and is possibly not even being manufactured any longer (at least in any quantity). The demand for carbide was no doubt from some obscure industrial process rather than for caving or mining use in any case. Perhaps the era of caving with an acetylene lamps is coming to a close, once remaining stashes in people's sheds have all been used up. It will be much missed, especially once the faff factor has faded from memory.
