40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production - diisocyanate emissions.
(a)Diisocyanate storage vessels. Diisocyanate storage vessels shall be equipped with either a system meeting the requirements in paragraph (a)(1) of this section, or a carbon adsorption system meeting the requirements of paragraph (a)(2) of this section.
(i) During each unloading event, the vapor return line shall be inspected for leaks by visual, audible, or an instrumental detection method.
(ii) When a leak is detected, it shall be repaired as soon as practicable, but not later than the subsequent unloading event.
(2) The storage vessel shall be equipped with a carbon adsorption system, meeting the monitoring requirements of § 63.1303(a), that routes displaced vapors through activated carbon before being discharged to the atmosphere. The owner or operator shall replace the existing carbon with fresh carbon upon indication of breakthrough before the next unloading event.
(1) The pump shall be a sealless pump; or
(i) The pump shall be completely immersed in bis(2-ethylhexyl)phthalate (DEHP, CAS #118-81-7), 2(methyloctyl)phthalate (DINP, CAS #68515-48-0), or another neutral oil.
(ii) The pump shall be visually monitored weekly to detect leaks,
(A) The leak shall be repaired as soon as practicable, but not later than 15 calendar days after it is detected.
(B) A first attempt at repair shall be made no later than 5 calendar days after the leak is detected. First attempts at repair include, but are not limited to, the following practices where practicable:
(1) Tightening of packing gland nuts.
(2) Ensuring that the seal flush is operating at design pressure and temperature.
(c)Other components in diisocyanate service. If evidence of a leak is found by visual, audible, or an instrumental detection method, it shall be repaired as soon as practicable, but not later than 15 calendar days after it is detected, except as provided in paragraph (d) of this section. The first attempt at repair shall be made no later than 5 calendar days after each leak is detected.
(d)Delay of repair.
(iii) Repair is completed as soon as practicable, but not later than 6 months after the leak was detected.
(3) Delay of repair for pumps is also allowed if repair requires replacing the existing seal design with a sealless pump, and repair is completed as soon as practicable, but not later than 6 months after the leak was detected.