Let me start by saying that I may need to get out more! This is a nerdy post.
However, I have time today and I've been lucky enough to have climbed Sunday, Tuesday and am climbing tomorrow so I'm not too worried about being indoors on a sunny day.
I've been all over the net and have some near-definitive responses to queries/comments and some irrefutable FACTS
some of which I can back up with references from scientific papers.
OK, in no particular order:
--- use of an ordinary screwgate crab to link leg loops to waist belt.....
--- Old Smelly is.......
"Hmm NOT CONVINCED [about the horizontal Petzl Omni thing) Nic (Unless you are the Engineer who designed it I think the horizontal story is BS)
Petzl says that the Omni is a
"Semi-circular locking connector for fastening a
and you will see that it is shown in use horizontally.
HOWEVER it then goes on to say:
"The semi-circular part provides a place to attach lanyards and similar equipment. It can be used with personal fall-protection systems....and rescue systems. It can also be used for caving, climbing and mountaineering."
With regard to its use only horizontally, if you're using a rescue system or ascending/decending the rope, it's quite likely that the carabiner will be loaded in all three axes, despite its initial orientation so its use on a climbing harness in the way Old Smelly describes appears to be approved of.
Note the way that in the diagram the accessory loads (lanyards, ropes and by extension, belayed climbers) are shown sliding from side to side in the D part of the crab. It stands to reason that you can use it vertically in the presumed "Alpine Bod" scenario.
--- Nylon, UV radiation and harness life.
Few manufacturers will come straight out and give a definitive lifetime age limit for any harness due to obvious factors like use, storage, exposure to unknown chemicals etc.
The most excellent Mammut company in Switzerland do stick their necks out and say (excuse the wierdly translated German)........
"Even if harnesses are one of the most robust pieces in climbing gear, their livespan are not unlimited. By regularly controlling the weakest points of ones harness, one can scrap the harness before it‘s too late.
Harnesses olden almost as the ropes, because they are built in the same materials. On the other hand, they are largely over-dimmensionned, and do not have to be as dynamic as the ropes. The danger of sharp edge fall is
also no question for a harness. Nevertheless, you should you for safety reasons, scrap your harness after a certain time. The following table gives guidelines, which should of course be adapted to individual cases. As an example, a harness wears off faster in a granite chimney as in overhangs.
Moreover, you should control on a regular basis, and after every important fall, every single stitch, as also wear-prone zones. Special attention should be given to the tie-in area. If any of these elements is damaged, it‘s time for a change! And since your life depends on your harness, the rule is: better too early than too late."
And Mammut suggest an approximate lifespan for harnesses:
Never used - 10 years maximum
Rarely used: twice per year - up to 7 years
Occasionally used: once per month - up to 5 years
Regularly used: several times per month - up to 3 years
Frequently used: each week - up to 1 year
Constantly used: almost daily - less than 1 year
Now, remember that harnesses and ropes are made of the same materials, Nylon 6.6 or Nylon 6 (known as Perlon).
"Nylon is slightly less dense and has better abrasion resistance than does polyester. It also has better elongation and energy absorption properties than polyester. Neither is prone to mildew and both have comparable melting points and are dimensionally stable over a wide range of temperature. However, nylon loses more strength when wet and sunlight has a greater deterioration effect on nylon when compared to polyester. Finally, acids (eg..urine and battery acid ect...) attack nylon whereas bases (eg..caustic soda and lime ect...) attact polyesters. With respect to the above, nylon is the first choice for the manufacture of climbing ropes."
Chemists say........"Ultraviolet radiation, either alone or in combination with oxygen, heavy metals, etc. profoundly influences the mechanical behavior of most polymers. Indeed, the preparation of photodegradable resistant polymers, or of additives to prevent or reduce the photodegradation of polymers, have been major fields of investigation."
Pitt Schubert, President of the UIAA safety commission says......"UV radiation does not damage ropes. Nylon is UV stabilised and only the colour will be lost."
"The suggested life span of 10 years which has been given for ropes is to help the user determine life span . However, after contact with ICI it was found that although after 10 years there was a measurable degradation in nylon (not just in ropes, but all nylon textiles) ageing itself would not cause a rope to break, unless it was loaded over a sharp edge."
So, yes UV is probably not great, but your harness won't disintegrate in a short time, if at all.
Nylon is UV-susceptible, but these days UV stabilisers have mitigated that effect.
Finally --- Strength of belay loops
Old Smelly says........"I have it on good authority that harnesses are made to be 14 KN strength with the belay loops strengthened for wear & tear."
My post above said...."the average belay loop is approx 22-26 kN in any direction."
This info comes from destruction testing results of belay loops. Evidence-based.
I'll stop now. I'm going into the sunlight! Argh!!!...........it burns!!