MH lamps do not make any more UV than a MV lamp (unless it is a UV MH).

True, I forgot to mention UVs about MV.
Furthermore there are some regulations (depending on the country I guess) that require to use MH lamps within a closed fixture (i.e. behind a glass) because of the risks of explosion near EOL, which should reduce the amount of UVs, while most of mercury vapor lamps are bare.

Actually I meant that MH lamps can be used indoor because of their high CRI (while most of MV and HPS are used outdoor, in factories, in train stations, etc.): you see a lot of them in stores, commercial centres, etc., but I wouldn't recommend them indoor because of the high emission of UVs.

MV's are used indoors as well.
And many higher wattage MH's used indoors are of the guarded arctube type, these do not need any external protection against explosion (the guard absorb the energy, so the outer withstand it). And these emit the same amount of UV as the MV's.

For all lamps, so both MV and MH are strict limits about the UV emission, these ensure the lamps are safe.
The 400W and above have these limits higher then those considered safe for long therm exposure, so only these have to be additionally shielded (again both MV and MH) if placed low. But these are used only in installations, where they need protection against elements due to other reasons anyway.

MV lamps are used indoor with high illuminances, but it's pretty rare compared to MHs. Even in the 80's I haven't seen many MVs installed in stores, supermarkets, cafeterias, waiting rooms, etc., while you can see MHs  everywhere.

If I had a store and had to choose a HID lamp type:
- I might consider MV but I would reject the option due to the colour rendering (regardless UV emission);
- I may consider MH because if the high CRI and the nice tints, as many store managers do, but due to high illuminances in a store I would personally avoid installing too many of MH lamps because of the UVs.

So my answer to the topic meant: I like MH for its great tint, but it is not perfect though.

BTW thanks for the rest of you reply, this is very interesting

My favourite is mercury vapour. As a nipper I saw much of my home city converted to LPS in the 1970s and 1980s and I hated the orange pall which took over every city and town in Britain, so it is probably partly down to fond memories of seeing the cool white lights and the way the trees and grass came to life. When changed for LPS, the trees and grass looked dead and the paths amongst them dark, shadowy and really seedy.

Part of the problem with LPS in England was due to the wide angle lanterns almost universally used, I only ever saw one village lit with full-cutoff lanterns when on my travels. With white (or even green/blue) light, even using the old wide-angle lanterns, your night vision cells take over at low light levels and even moderate light-spill blends in well with natural moonlight/dusk etc.. Not so with LPS (or even HPS) as you will always see an orange glow if you can see it at all, making it much more visually intrusive. This is why LPS light pollution is such a problem even when present at low levels.

LPS is fine for industrial estates, some built-up areas especially terraced streets (those without trees) which reflect LPS well and rural highways/motorways (I'm even tempted to fit one in my entry if I can get hold of a 10W lantern) but totally unsuitable for areas with greenery, especially footpaths, the councils even fitted the things along the back alleys of houses so you couldn't escape the orange glow anywhere, however you couldn't see where you were walking as this highly efficient light source is not so when it is mostly absorbed by its surroundings.

From the early 1990s many LPS lanterns were replaced with HPS using proper directional optics, this gave a big improvement but greenery still does not show up at all well, so are they really still more efficient than MV in these cases?

MH does give a much better light than HPS but to me it looks harsher than MV and took me a bit of getting used to. Some of the newer daylight MHs do a fairly good job of simulating MV however.

Today many areas are getting MHs with tight beam angles, mine included (one of the first here! My area was used as a trial for the new lanterns). This has eliminated the glare and light-spill from the previous fixtures, in my case I no longer have my front bedroom bathed in dirty yellow HPS light yet the roads and pavements enjoy much better visibility even at lower light levels, due to the clean white light and not having your night vision ruined by the glare from the lanterns further down the street. You can actually see the night sky properly now, unlike many years ago when you had to travel miles out of town to do so.


Some of the jewellers' shops use(d) 80W mercury lamps  in their windows to highlight the merchandise, crystals and things look really nice under this light due to the distinctive spectral lines. There are also some larger stores here using MV, the pet warehouse at St Georges being one example. These IMHO look better than the MHs fitted in similar stores.


I don't dislike LPS, I just hated the way they were used absolutely everywhere for so long. Most of them have gone now.


The first time I saw a clear MV in operation was when I bought some from Eye Lighting! I love the way the 80W lamp lights the back yard up and I also use one in my Ikea half-moon uplighter in the loft, sometimes I put a coated lamp in this but I usually use a clear one as it gives a nice unique light.


BG

Why does (just out of curiosity) does EVERYONE like  lamps? (I like them too)

Wild guess for main reasons :

Mercury lamps installed 30 years ago still work out there every single night since (not usefull light output for such old lamps, but keep on starting and lighting up)

If there would be a deserted town that was abandoned 50 years ago and reconnected to power, old fixtures that were built to just last forever would light up perfectly like if they were installed yesterday. Though it would actually be the case with any lamp (even CFLs), imagination does its own work to guess what lamps are in those fixtures - nothing other than BT mercs (in odd cool fixtures) from the wildest imaginations

The yellow light is not pleasing in most night scenes, makes very visible light pollution in the sky, and color of plants under it (grass, trees) looks very bad. This calls against the 2 sodium lamps

MH is close to mercury in most other stuff except :

The light color of MH is more natural, therefore less standing out as artificial light, What would you expect in a community that is interested more by the effect of the light source itself than what it is lighting on

MH lamps have shorter life so won't appear in the "time machine" scenarios above (though actually there is nothing that would prevent MH from appearing in the village scenario - it even allready existed back then)

MH lamps tend to explode at EOL - making them appear as damaging light fixtures (that have plastic covers) and not suitable to open fixtures. Though this issue is heavily exxagerated - they dont have any problem related to this when in enclosed fixtures with glass covers, and there are open rated MH's for the other fixtures

LPS also makes a great lighting effect, much better than HPS. I like the "black and white effect" of them, as well as the greenish effect of  . The however, gives the WORST light, it is yellow but isn't monochromatic.

I've seen some nice yellow HPS lamps, something between standard HPS and white HPS that is actually somewhat pleasant. I also like the white sodium tint very much (which is more or less comparable to incandescent) and would like to see it widely used in existing HPS fixtures.

I do like the standard HPS color - just not everywhere but where the lighting is strong enough that it actually lights the area with the same color as the HPS itself is - ie high intensity floodlighting

Hi All

My faourites would be MV. LPS and good old fluorescent!

"BG101, just imagine if it were not for our 1970s energy crisis, we could still have been like Australia with mercury and fluorescent lamps still in use , I would like to see more high powered Halides on our roads but I do prefer SON to SOX.

I have always liked the cool glow of mercury vapor lamps. When I was younger my parents belonged to an RV club and we would go camping every year at different Parks, and I would always meet new friends. Nothing sets the mood like four teenagers standing under a mercury vapor nema fixture at night talking about girls while a faint buzzing sound from it's ballast can be heard in the background.  Ah the good ole days.

  would be my favorite,  for yard lights and in general because of the long life especially in older lamps such as the Westinghouse lifeguard especially in DX phosphor, most would last between 200,000-300,000 hours before becomming dim
MV lamp life seems best when operated base up when on a CWA ballast

@Slipperypete Same here with school trips into fieldschools. Best times

Something to think about, my Norelco yard light above my garage was a and just recently the bulb had burnt out. I looked at the date code on it,  and it was made in may 1970.  The best part is the light was wired in to the porch light circuit so it was always used every night from dusk to dawn for 42 years!