Author Topic: T8 fluorescents, was there any benefits?  (Read 1840 times)
Desultory13
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T8 fluorescents, was there any benefits? « on: April 08, 2021, 06:59:41 PM » Author: Desultory13
Now that the lighting industry will soon be closing the chapter on fluorescent lighting I wonder was there any benefit to T8s as opposed to T12s?
When I came into the electrical trade back in 2003 the switch from T12 to T8 was in full swing.
All the years that I spent installing them I just never really thought that there was much benefit to them.
I think they were somewhat more energy efficient and gave off a little more light but I didn't think that it was enough to put an end to the tried and true workhorses, the T12s.
I do feel that their electronic ballasts were never as reliable as the magnetic ones for T12.
Personally I think that the whole concept behind the T8s got started back in the early 90s when even then manufacturers were looking for a way to cut costs and the answer was T8.
Smaller diameter tubes with less mercury and phosphors.
As well as the electronic ballasts with less copper.
I always felt that the real noticeable benefit in fluorescent lighting was in the second half of the 90s with the 2x2 parabolic troffers that used the twin tube Biax lamps, now those were bright and the fixtures were unobtrusive, sleek, and compact.
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wide-lite 1000
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Re: T8 fluorescents, was there any benefits? « Reply #1 on: April 08, 2021, 09:09:35 PM » Author: wide-lite 1000
I've noticed that the T-8's in my carports can handle the cold WAY better than the T-12's do . Plus , the 32w T-8's seem (to me anyways) to be brighter than the 40w T-12's . At work , we have some 8' 2 lamp H.O. strips which as they die are being replaced by 2 - 2 lamp 4' T-8 strips mounted back to back and if you look at floor brightness, the T-8's are WAY brighter than the 8' H.O.'s.

 Now , all of what I've said is based on comparing 20yr old Magnetic T-12 to less than 10yr old or newer Electronic T-8 .
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funkybulb
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Re: T8 fluorescents, was there any benefits? « Reply #2 on: April 08, 2021, 09:30:21 PM » Author: funkybulb
First the F32 T8 came out in early 80s and orginally ran on rapid start.  Electronic ballast did not take off until late 1990s
For the T8. 

 Now for T12 u really need to compare a old school CW T8 to a old school T8s it will blow them out of the water.  The first wave of T12 bans started in july of 1995. I found this out cause I cant buy F40D in late 1995.

That when lamps got dimmer and 700 CRI for full wattage until 2012.  That leave us a very few Last remainimg T12s.

This why T8 seems to be brighter than T12.  Ive seen more DX  tubes sold in today era as it just about only decent T12 left.

So it best to compare T8 DX with T12 DX on full power ballast.

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Desultory13
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Re: T8 fluorescents, was there any benefits? « Reply #3 on: April 08, 2021, 09:43:44 PM » Author: Desultory13
The way I see it the only to really compare T8s and T12s is to have them both on electronic ballasts.
Electronic don't seem to be very popular around here for some reason but they do allow lamps to run brighter.
My only problem with them is they don't last as long as magnetic.
Having said that the problem seems to me was with the ballasts themselves more so than the lamps.
Instead of creating a whole new T8 tube why didn't manufacturers simply improve the ballasts for T12s?
I mean the T12 was available in a huge variety of colors and sizes I just don't really see why the T8 was needed.
All that had to be done was simply build more efficient T12 ballasts.
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funkybulb
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Re: T8 fluorescents, was there any benefits? « Reply #4 on: April 08, 2021, 11:09:54 PM » Author: funkybulb
What i mean is F32T8 rapid start and F40t12 rapid start.
  Infact I have ran F32T8 on F40T12 preheat ballast.  That would overdrives the lamp. 

 Thing is I have 12 volt electronic GE rapid start from the early 1970s that Takes F40T12.
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joseph_125
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Re: T8 fluorescents, was there any benefits? « Reply #5 on: April 08, 2021, 11:22:40 PM » Author: joseph_125
Yeah T8s tend to be rated down to 0F which is a cheaper option than HO which was rated to -20F for most homeowners. I believe technically T12s were rated to 50F or something around there.

T8s were introduced by Sylvania in 1982 and the first ones were designed to be run on a magnetic rapid start ballast, just like the T12s. Electronic ballasts I believe only came out during the 90s. They also took up less room and were probably also cheaper to make compared to T12s.

I think the main advantage of the T8s were the newer triphosphors which were both more efficient and allowed for better CRI compared to the old halophosphors that were used on the T12 lamps at the time. Operation on electronic ballasts also allowed for higher light output too.

They did attempt to make better ballasts for T12s, first attempts were the energy saver magnetic T12 ballasts like Advance Mark III which typically drew .65A instead of .80A for a two lamp T12 ballast. Then some companies like Advance tried making cut out T12 ballasts, the Mark IV PowrKut ballasts which had a small electronic circuit to cut out the cathode heating supply to save a few watts. Finally by the 2000s fully electronic T12 ballasts started to be common for general lighting.

There was also two bans related to ballasts, the first one banned the .80A ballasts in favour of the .65A units (maybe sometimes during the 90s). The second one banned the .65A units in favour of electronic ballasts. (effective 2005 for new luminaires, 2010 for replacement ballasts) This is one of the reason why if you ask for a T12 ballast at the supply counter you get a electronic unit instead of a magnetic one.
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Michael
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Re: T8 fluorescents, was there any benefits? « Reply #6 on: April 10, 2021, 03:37:55 AM » Author: Michael
In Europe and Switzerland the transition to T8 already started in the very late 70s / early 80s. Here the energy saving and especially in new installations the use of tri- phosphor tubes were biggest gain. The T12 remained as a more specialist lamp in outdoor/ industry niche and it is still seen very rarely today.
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trmligt3131
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Re: T8 fluorescents, was there any benefits? « Reply #7 on: April 10, 2021, 02:46:07 PM » Author: trmligt3131
The T12 40w fluorescent lamp is installed in the luminaire in the warehouse near my house. The luminaires have not been used for a long time and are very old (tms armature). One day maybe I will remove the lamps, but I hope they will burn.
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f36t8
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Re: T8 fluorescents, was there any benefits? « Reply #8 on: April 14, 2021, 03:26:34 PM » Author: f36t8
As monkeyface already said, in "230V-land", the T8 tubes were already very widespread much earlier. In fact, I did not know that T12 ever existed until about 2005-2010 where I saw one by chance (I was born in the early 90s and started collecting lights in the late 00s).

The retrofit tubes here were/are not bad at all, except for very cold temperatures (which is not so common in most of Europe anyway). The 18 W, 36 W, and 58 W tubes directly replaces the 20 W, 40 W and 65 W T12 tubes and worked fine on the usual preheat choke ballast common here. Aside the (admittedly small) energy saving, I think later the reduced phosphor amount required because of the smaller surface area was one of the main motivations to reduce the tube diameter, for the triphosphor tubes to save costs. Actually, they remain my currently preferred indoor lighting source for general use. I realize this is a different situation than in the US, with different ballast designs.

One possible benefit is when reflectors are used: the reflector can be made smaller because the tube is more compact. On the other hand, if the tube is visble and naked, a larger tube would produce less glare.
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Michael
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Re: T8 fluorescents, was there any benefits? « Reply #9 on: April 15, 2021, 06:36:39 AM » Author: Michael
T12 tubes are still available here but only as a specialist lamp with starterstrip (I.R.S.). We used to use them in street lights till 2017 and there are still installations which requires these tubes in some of our underpass lights.

In 1978 the first T8 energy- saver tubes were introduced as 18W, 36W and 58W and later in the 1980s the portfolio was extended with 23W, 38W, 36W-1m and 70W replacing T12 types of 25W, 42W, 40W-1 and 75/85W.


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Re: T8 fluorescents, was there any benefits? « Reply #10 on: May 09, 2021, 04:23:55 AM » Author: LightsDelight
Personally my benifits are that they are just heaps brighter and have a better colour. I have run T12s in the shed for a but of fun and it wasn't very long until I went right back to triphosphor T8s. So much nicer colour was was much brighrer.
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kai
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Re: T8 fluorescents, was there any benefits? « Reply #11 on: July 09, 2021, 03:42:35 PM » Author: kai
As monkeyface already said, in "230V-land", the T8 tubes were already very widespread much earlier. In fact, I did not know that T12 ever existed until about 2005-2010 where I saw one by chance
I was also pretty surprised when I back in 2011 saw this one. Already in the eighties Narva had replaced them by T8 and the only remaing T12 lamps were the Soviet 40 watts LB (535) that had to supplement the domestic supply.

It's really a completely different story than the incompatible T8 lamps in "110V-land".
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