To:	Jeff Telander						From:	Dave Reeves 

Project File						Date:	March 17, 2008

Re:	Mineral Wool Production – Actual versus Allowable Emissions

Source Category	Emission Point	Format of Primary (MACT) Standard	Could
Possibly Calculate Allowable?	Info Needed to Calculate Allowable
Emissions

Mineral Wool	Cupolas	Emission Limits:

kg PM/ Mg melt

kg CO/ Mg melt	Yes	Amount of melt

	Curing Ovens	Emission Limit:

kg formaldehyde/Mg melt	Yes	Amount of melt



We reviewed all of the reported emissions data in NEI and TRI, as well
as the emission limits in the Mineral Wool Production MACT standard and
state operating permits.  In general, all of the emission limits are
based on production levels (e.g., mass of pollutant allowed to be
emitted per mass of material melted).  Even though production levels
could be increased at most of the currently operating facilities, there
are equipment and process limitations on how the melting furnaces
(cupolas) are operated – which limits the potential (allowable)
emissions for a given facility.  Market forces also impose production
caps on existing facilities and probably account for much of their
current excess capacity.  The cupolas are considered batch operations,
but are run on a continuous or semi-continuous basis to save time and
energy to heat up the furnace for each batch.  Because melting
operations are the production limiting process at these manufacturing
facilities, the reported emissions are representative of the current
market and are believed to at the highest level (since the overall
mineral wool market is declining).  

We also reviewed data from the North American Insulation Manufacturers
Association (NAIMA) in response to a request for summary MACT compliance
test data for mineral wool production facilities.  Six facilities
reported cupola particulate matter (PM) emissions and three facilities
operating bonded lines reported formaldehyde emissions from curing ovens
– see attached summary table.

The arithmetic average PM emission rate for all cupola PM emissions data
is 0.044 pounds PM/ton melt.  (We also calculated individual facility
averages and means and came up with basically the same value.)  The
average formaldehyde emission rate for all curing oven formaldehyde
emissions data is 0.038 pounds formaldehyde/ton melt.  Allowable PM and
formaldehyde emission rates under the Mineral Wool MACT standard are 0.1
pounds PM/ton melt and 0.06 pounds/ton melt, respectively.  The
allowable PM emission rate is approximately 2.3 times higher than the
average of the reported PM emission rates (0.1/0.044).  The allowable
formaldehyde emission rate is approximately 1.6 times higher than the
average of the reported formaldehyde emission rates (0.06/0.038).      

Based on these reported emission rates and the equipment and process
limitations, we are recommending that allowable emissions be estimated
to be 2 times the actual emissions for each facility for purposes of the
risk modeling.  We believe that a 2X factor applied to the most recent
reported emissions is realistic and does not grossly overstate potential
emissions.

 

