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t8 vs t12 and headaches

Discussion in 'Lighting' started by RobR, Nov 8, 2005.

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  1. RobR

    RobR Guest

    Employees have been complaining about headaches in the work place.
    The lights we currently have are T12 fluorescents and buzz and flicker
    badly. The landlord brought in a friend who suggested T8's with electronic
    ballasts. I'm wondering if something with a higher frequency rate, but
    that's still fluorescent would solve any light related headache and
    fatigue problem? Any particular bulb temperature recommendations?
  2. RobR

    RobR Guest

    btw the nature of the job is staring at computer screens all day (software
  3. SQLit

    SQLit Guest

    T-12's can flicker, explained very well in other posts. Has anyone tried
    replacing the lamps or ballasts to stop the flickering? Fluorescents are not
    forever they do wear out.
    T-8's can solve/help the flicker problem.

    Before jumping into the soup has anyone asked some questions?
    When did this start? What was the temperature? Are the existing
    ballasts/lamps operating at a lower temp? What changed?

    When I sat under the lights all day the first thing I did was to reduce the
    lighting by half above my desk. Glare makes a big difference for me. Some
    times changing the lenses on the fixtures can help as well, back to the
    glare issue. An egg crate lens can help cut the glare.
  4. RobR

    RobR Guest

    Thanks but I just want these lights out. I don't want to throw money
    at new ballasts that could very likely buzz anyway. I have a total
    of three light fixtures that I need to replace and about a $500 budget.
    I'm just looking for something energy efficient, that doesn't cause
    and has a color temperature that's reasonably natural.
  5. SQLit

    SQLit Guest

    As others have said the electronic ones can make noise as well. Look for a
    sound rating of "A" on the ballast label. Your going to pay more for them.

    $500 seem like a lot of money for 3 fixtures unless your going to buy new.
    Then it may not be enough.

    Color is testy subject. I did a lighting retrofit with 4200K lamps. They
    were a bit towards the yellow spectrum. Looked good and preformed great as
    long as ALL the lamps were the same.
    We got a BUNCH of complaints until all the lamp on a floor were changed, a
    few days usually.
    There are some "daylight" bulbs, look good for those that need them. Tad
    more money.
  6. I would advise two things:

    1) Take the advice of others suggesting higher quality electronic
    ballasts. Although such ballasts are available for T12, they are mostly
    made for T8.

    2) Get the employees' monitors set to horizontal scan rates far above 60
    Hz. 60 and 56 are somewhat standard horizontal scan rates. I usually
    see 56 visibly flickering and sometimes see 60 visibly flickering.
    I do not see 72 nor 87 visibly flickering. (Since a popular setting
    with 87 Hz horizontal scan rate is interlaced, it may be noted as having
    a refresh rate of 43.5 Hz. The popular resolution with this rate often
    available is 1024 by 768.)

    - Don Klipstein ()
  7. RobR

    RobR Guest

    thanks for the advice, no issues on monitors, we run everything at high
    rates, even if it means dropping down the resolution.
  8. TKM

    TKM Guest

    How long have you been getting complaints?

    A flickering fluorescent lamp can drive people crazy (they usually just take
    it out); but people in offices have worked with T12 lamps on electromagnetic
    ballasts with their low level of flickering and buzzing for 55 years. They
    are still in wide-spread use, of course, even in rooms with computer

    Yes, T8 lamps on electronic ballasts will get rid of whatever flicker and
    buzzing there might be; but there are probably more serious lighting
    problems in that room.

    Do you get complaints about glare, too much (or too little) light, dark
    areas, poor color, bright reflections in the computer screens or a "gloomy"

    If so, switching to a T8 system won't fix those things although you'll
    likely get a brief respite from the complaints (the classic Hawthorne

    Typical fluorescent room lighting is not suitable for people doing computer
    intensive visual tasks and any money spent replacing lamps and ballasts will
    be wasted.

    Get someone more expert than the landlord's friend -- maybe even a
    professional lighting designer. That will cost $100-200. But if you really
    fix the problems, you will probably see a productivity increase (1-5% isn't
    uncommon) and happier employees. What's 1% of your payroll for that room

    Terry McGowan
  9. RobR

    RobR Guest

    Great advice. I emailed the landlord earlier today about what I was
    interested in doing and willing to discuss. I showed up at the shop
    today and he had already gone and replaced the lighting. Sigh.
    If this doesn't cut it, any recommendations on standing floor
    lamps? The complaints were headaches and fatigue. I myself
    could see the flickering, it made my eyes go crazy when I first
    walked into the room until i adjusted.
  10. TKM

    TKM Guest

    Well, let us know how the replacement lighting works out. At least you
    should get rid of the flickering.

    However, if you want to pursue the "floor lamps" idea, Here are some
    suggestions. By floor lamps, I assume that you're thinking about so-called
    "torchiere" fixtures that stand on the floor and direct their light onto the
    ceiling. The result is indirect lighting of the room.

    -As a lighting designer, I suggest that the indirect lighting be
    supplemented with task lights at the computer work stations so each person
    can adjust the level and angle of lighting to suit themselves. Indirect
    lighting in computer-intensive spaces is typically designed just to provide
    a low level of general lighting for circulation, not office work such as
    reading, filing, etc. Use fluorescent task lights -- even better if they
    have a dimmer. Give people some adjustable lights and knobs to turn and
    they'll quickly figure out for themselves what works best.

    -Use torchiers equipped with fluorescent lamps. Typically, such units are
    equivalent to older designs that used 300 watt incandescent halogen lamps.
    Here's one that's even dimmable for about $65.

    - Don't use halogen torchieres. (They are inefficient and hot).

    - Torchiere and task lighting fixtures with the Energy Star label meet
    published lighting quality, life and performance requirements.

    - I use 3500 Kelvins, 80+ CRI lamps for general office lighting. If your
    lighting level is low (20 footcandles or less) or if you use the torchiere
    approach, 3000 Kelvins is O.K. But, color, including lamp color choice, is
    highly subjective and will also depend upon the colors in the room. It's
    best to try a couple of lamp colors to see what the occupants like.

    - Don't use halogen torchieres.

    - You'll see companies promoting "full spectrum" lighting. IMO it's
    overpriced and offers few benefits except perhaps better color rendering for
    certain colors. Do you have any color-critical visual tasks?

    - Remember that with indirect lighting, the brightest most visible thing in
    the room is probably the ceiling. Is it worth looking at?

    - Indirect lighting works best with a high-reflectance ceiling - flat white
    finish preferred.

    - Books have been written about lighting for rooms with computer-intensive
    tasks. But there is a good summary in the Advanced Lighting Guidelines,
    2003 Edition. You can read that free at:
    Look particularly at Section 4.3.2 Pages 4-15 to 4-21.

    - Oh, yes, don't use halogen torchieres.

    Terry McGowan
  11. RobR

    RobR Guest

    Thanks for the posts, I'm aware there may be other causes but
    it was clearly evident that the current lighting is a problem. The
    flickering was immediately visible to me upon entering the room
    and at least one of the ballasts was buzzing loudly. So step 1
    is fix that problem, and I wanted to make sure that it was done
    properly. The landlord didn't exactly help here since he didn't
    bother to wait to hear from me as he had agreed, so step 2
    is if the problem continues, check the lighting he installed and
    then move on to other issues. There are no appliances (other
    than a microwave) and all the HVAC stuff is outside the unit
    so hopefully CO isn't an issue.
  12. David Lee

    David Lee Guest

    indulged in petty argument with !

    This exchange is totally off-topic and in breach of news-group etiquette.
    Kindly conduct your arguments in private and do not bring them into this

  13. David Lee

    David Lee Guest

    No it wasn't! After issuing your warning you proceeded to continue a
    slanging match that obviously had been occurring elsewhere and was of no
    relevance to us.

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