Slotted guidepoles are anti-rotational devices that have slots or holes for gauging purposes. The slots or holes provide an opening that allows the operator to see the liquid surface and take samples. The openings also provide a path for vapors to escape the tank. Organic emissions from slotted guide poles are significant, especially when wind movements through the slots creates a pressure differential that draws vapors out of the tank. The proposed amendments require the use of gaskets, wipers, and pole sleeves to minimize evaporation. Retrofit kits for slotted guidepoles are readily available which will significantly reduce emissions and can be installed without taking the tank out of service.
Staff also propose to slightly modify the requirement for primary metallic-shoe type seals used in internal floating roof tanks. A separate criteria is needed for internal and external floating roof tanks for the minimum distance required to extend above the liquid surface for a metallic shoe type seal. This is to clarify requirements in the NSPS for metallic-shoe-type seals used only on external floating roof tanks to meet a minimum vertical distance above the liquid surface of 24 inches. For existing internal floating roofs, staff is proposing a minimum vertical distance of 18 inches, instead of the present 24 inches.
Two administrative rule amendments are also included:
- The current rule allows tanks to be taken out of service for short periods of time for routine maintenance or to change stock provided the District is notified when this occurs. This is to encourage proper maintenance and reduce potential long term emissions from non-compliance. The amendment would require a certification that the tank is in compliance prior to being taken out of service and will require minimization of emissions while work is being performed.
- The current rule allows an exemption for preventative maintenance of a vapor control device or secondary seal, or for a roof repair, or for the inspection of a primary seal. The proposed amendment would require 7 day advance notification to the District of secondary seal repair and certification of compliance for prior to commencement of the work for improved rule enforceability.
The workshop draft of the rule contained additional elements calculated to reduce emissions from organic liquid storage by at least another 8 tons/day. These proposals would:
- Require some organic liquids presently stored in higher emitting fixed roof tanks to be stored in floating roof tanks or to be controlled by vapor collection system.
- Require that tank roof seals be upgraded when replaced with high quality seals based on emission control effectiveness and longevity of service.
- Require more frequent inspections of floating roof tank seals.
- Require fittings on external and internal floating roof tanks and fixed roof tanks connected to vapor recovery to meet certain leak tight criteria to minimize emissions.
- Require improvements and modification to gas-blanketed tanks.
- Add new and improved compliance requirements.
These requirements are not in the present proposed amendments. However, Staff still intends to bring these proposals to the Board in the near future.
The cost effectiveness of these amendments is approximately $1250 per ton of VOC emissions reduced. The amendments affect petroleum refineries, gasoline bulk plants and terminals, chemical manufacturing facilities and some manufacturers who use significant amounts of organic liquids. The socioeconomic analysis prepared for the amendments to Regulation 8, Rule 5 indicated that the proposals would not have a significant impact on affected facilities.
Based on an initial study performed for this project, staff have determined that there is no substantial evidence in light of the record before the District that for the proposed amendments to Regulation 8, Rule 5 would have significant effect on the environment. Pursuant to Public Resources Code, Section 21080 (c) and CEQA Guidelines 15070, staff recommend adoption of the attached negative declaration.
