Do
you change your spark plugs on a regular basis, or do you wait
until your car won't start at an intersection? When you do change
your spark plugs, do you tell the shop to change just 1 or 2 of
them? We hope your answers were no. But so many buildings
take this approach to their lighting systems. Only a small percentage
have lighting maintenance programs where all lamps in an area
are replaced on a regular basis, even before the lamps have failed.
This process is referred to in the industry as group relamping.
The alternative, which is to replace lamps on an as required basis,
is referred to a spot relamping.
Maintain Light Levels
The primary advantage
of group relamping over spot relamping is that group relamping
ensures that lighting levels are maintained at higher levels.
As time progresses,
lamps will deteriorate and dirt will accumulate. Lamp failures
will start to climb and dirt will continue to accumulate. The
combination of failures, reduced lumen output and dirt accumulation
result in a reduction of light level by as much as 30% of initial
output after only 2 years.
With spot relamping,
when lamps are replaced only when they burn out, it is rare that
the lenses and luminaire surfaces are adequately cleaned.
Occupant Satisfaction
In buildings with group
relamping, occupants tend to be more satisfied because they do
not have to complain about the light being too dark in their work
area.
Cost Savings
The cost to replace
a lamp is mostly labour. It takes on average 20 minutes for a
random lamp replacement. On the other hand, group relamping averages
2 to 3 minutes per lamp. Thus, planned lighting maintenance brings
down labour costs.
What Happens After
a Lighting Retrofit?
If you have taken the
smart move to save energy by retrofitting your lighting system,
you need to maintain it. A group relamping strategy should be
considered for the same reasons mentioned above. Typically, group
relamping should be completed after 4 years but this will depend
on the operating hours of the facility.
In many instances, it
is even MORE important to maintain your lighting system after
a retrofit than before.
Taking into account
all the factors in a retrofit, including improved lamp lumen depreciation
for T-8 lamps, reduced heat from the ballast, and improved optics
of the luminaire, when you convert a 4 lamp 2' x 4' luminaires
to 2 T-8 lamps and a specular reflector, the lighting levels are
approximately 80% of the original system. In most cases this is
fine: many buildings that were built over the last 20 years were
designed for over 70 foot-candles and a reduction is acceptable.
But because the "waste" has been eliminated, it becomes
important to pay greater attention to maintaining the lighting
system.
Other Rewards
Group relamping offers
a number of other benefits:
