Equipment using aqueous solutions is permitted by rule, providing the
conditions of this section are met.
(1) This section authorizes the following operations:
(A) anodizing, chromate conversion coating processes, electroplating,
electrodeposition, electroless plating, electrolytic polishing, and electrolytic
stripping, as follows.
(i) For plating onto or stripping from any basis substrate,
only brass, bronze, cadmium, copper, iron, lead, nickel, tin, zinc, and precious
metals may be used.
(ii) Chromic acid shall not be used in any step of a process
which involves electrical current, air agitation, or any other factor which
causes the chromic acid to bubble or mist.
(B) cleaning, electroless stripping, etching, or other surface
preparation and finishing, not including chemical milling or electrolytic
metal recovery and reclaiming systems.
(2) Operating conditions.
(A) Hydrochloric acid tank operating conditions shall not exceed:
(i) a temperature of 100 degrees Fahrenheit and a hydrochloric
acid concentration of 19.0% by solution weight; or
(ii) a partial pressure of 0.5 millimeters of mercury.
(B) Hydrochloric acid in any state, and any aqueous solution
which bubbles or mists due to electrical current, air agitation, or any other
factor shall be used in an enclosed building. If the doors and windows of
the building are open for any reason other than temporarily for access, emissions
shall either be:
(i) captured and exhausted using forced air through a stack
with an unobstructed minimum vertical discharge of four feet above the peak
of the roofline; or
(ii) controlled with a fume suppressant.
(3) If a facility cannot comply with the hydrochloric
acid temperature and concentration limits in paragraph (2)(A)(i) of this section,
then to demonstrate compliance with paragraph (2)(A)(ii) of this section,
the maximum hydrochloric acid temperature and concentration for each tank
shall be recorded daily. At least once per month, the recorded data shall
be converted to partial pressure. All data shall be maintained for the most
recent 24-month period.