From: Dave Conway <rsidave1@gmail.com>

Sent: Wednesday, April 23, 2014 9:03 AM

To: Boyd, Rochelle

Subject: Re: Sweat Furnaces

Primary charge door opening is during charge is 6' X 4' Door is open for 20 seconds (2 times per 

hour). During clean out of primary the door opening is 6' X 2' for about 60 seconds (4 times per 

hour). The holding chamber door full opening is 3' X 4' but during operation it is opened 3' X 

1.5' just for skimming once an hour for about 60 seconds. Hope this helps. The only meters I 

have are angled draft gauge and digital pressure gauges for reading water column inches of 

pressure. I went on line to find a conversion chart to come up with the number I gave you. But I 

was somewhat concerned that there was no correction for the size of the opening. I hire 

environmental engineers to come up with the numbers I need for permits and setting up for 

stack tests and learn from them but this is a new one for me. I appreciate any of your feedback. 

Thanks

From: Dave Conway [mailto:rsidave1@gmail.com] 

Sent: Tuesday, April 22, 2014 6:06 PM

To: Boyd, Rochelle

Subject: Re: Sweat Furnaces

Hi Rochelle:

I looked in the ACGIH hand book chapter 10, more specifically in the foundry operations 10-20 

to 10-25. I see nothing there that applies to our furnaces. We do not need collection hoods for our 

furnaces since we are maintaining a negative pressure in the furnace from our tangent type of 

flow in our afterburner. We have a negative pressure of .04 to .06 wc." at the front door (charge 

and clean out) and negative 0.10 at the holding chamber access door.That calculation to fpm 

from wc pressure the square root of .06 which is 0.24 x 4004 which comes out to 897 fpm.

It is rare that any of our customers have collection hoods over the furnace doors. The ones that 

have did it because the old afterburner technology did not create enough draft or thy did not 

perform proper maintenance on door seal areas. They have since, removed the hoods because 

local air quality control agencies told them it was now a separate source and they would have to 

capture those emissions. Instead, we upgraded the afterburner on those units and repaired the 

door seal areas. Our average flow in these furnaces is around 5600 acfm with stack velocities 

average of 0.12 wc" delta P.

I am attaching a copy of a stack test performed in Detroit on one of our units with this type of 

afterburner system on it. You will see that these units are very control efficient.
Let me know if you were wanting something else.

Regards,

Dave Conway, Member

Recycling Services International, LLC

US Furnaces, LLC

20 Roosevelt Blvd.

Cohoes, NY 12047

518-424-1168

From: Boyd, Rochelle 

Sent: Monday, April 07, 2014 8:00 AM

To: 'dave@recyclingfurnaces.com'

Subject: Sweat Furnaces

Mr. David Conway

Recycling Services International, LLC.

20 Roosevelt Blvd.

Cohoes, NY 12047

Dear Mr. Conway:

I’m writing with regard to capture and collection systems on sweat furnaces in the U.S. The 

Secondary Aluminum NESHAP (published in the Federal Register on March 23, 2000) states:

§ 63.1506 Operating requirements

“(c) Capture/collection systems. For each affected source or emission unit equipped with an 

add-on air pollution control device, the owner or operator must:

(1) Design and install a system for the capture and collection of emissions to meet the 

engineering standards for minimum exhaust rates as published by the American Conference of

Governmental Industrial Hygienists in chapters 3 and 5 of ‘‘Industrial Ventilation: A Manual of 

Recommended Practice’’ (incorporated by reference in § 63.1502 of this subpart);

In your experience with designing and servicing sweat furnaces, are sweat furnace designs 

evaluated with respect to American Conference of Governmental Industrial Hygienist (ACGIH) 
guidelines? For example, are you aware of any sweat furnaces that have collection hoods above 

the furnace openings? Are the emissions capture systems typically evaluated with respect to 

ACGIH guidelines? If not, how is the ventilation system evaluated?

Thanks very much for any help that you can provide on this issue.

Rochelle Boyd, Environmental Engineer

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Sector Policies and Programs Division

109 T.W. Alexander Drive, RTP, NC 27711

Mail Drop D243-02

Ph: (919) 541-1390 Fax: (919) 541-3207