(a) The provisions set forth in this subpart apply at all times.

(b) You must not shut down items of equipment that are required or utilized for compliance with the provisions of this subpart during times when emissions are being, or are otherwise required to be, routed to such items of equipment.

(c) Startup begins when the wool fiberglass glass-melting furnace has any raw materials added and reaches 50 percent of its typical operating temperature. Startup ends when molten glass begins to flow from the wool fiberglass glass-melting furnace. For cold-top electric furnaces, startup ends when the batch cover is established and the temperature of the glass batch-cover surface is below 300 °F.

(d) Shutdown begins when the heat sources to the glass-melting furnace are reduced to begin the glass-melting furnace shut down process. Shutdown ends when the glass-melting furnace is empty or the contents are sufficiently viscous to preclude glass flow from the glass-melting furnace.

(e) During periods of startup and shutdown in a cold-top furnace that is routed to a baghouse during normal operation, you must establish the batch cover and operate your furnace according to the following requirements during startup and shutdown:

(1) You must keep records showing that you used only natural gas or other clean fuels to heat each furnace; and

(2) Except after batch cover is established, you must keep records showing that you used only cullet as a raw material during the startup of each cold-top furnace; and

(3) Once a batch cover is established and a control device can be safely operated, you must keep records showing that furnace emissions were controlled using air pollution control devices operated at the parameters established by the most recent performance test that showed compliance with the standard.

(4) During periods of shutdown in a cold-top furnace, until the conditions above the glass reach a point at which the control device may be damaged if it continues to operate, you must keep records showing furnace emissions were controlled using air pollution control devices operated at the parameters established by the most recent performance test that showed compliance with the standard.

(f) During both periods of startups and shutdowns for all furnace types other than cold-top furnaces, you must operate each furnace according to the following requirements:

(1) You must record the type of fuel used to heat the furnace during startup and shutdown to demonstrate that you used only natural gas or other clean fuels; and

(2) You must keep records showing that furnace emissions were controlled using air pollution control devices operated at the parameters established by the most recent performance test that showed compliance with the standard.

[80 FR 45336, July 29, 2015]