1. Colorado Reg. 7 2014 Revisions
Storage Tank Emission Management
Jul 10 | 2014
Marley Bain

2. Reg. 7 Revisions – Overview
Revisions to Reg. 7 adopted February 2014, effective April 2014
AQCC Regulation Number 7 – Control of Ozone Via Ozone Precursors and Control of Hydrocarbons Via Oil and Gas Emissions (VOC regulation)
Section XII and XVII focus on Oil and Gas emissions
XII: Ozone non-attainment area
XVII: State-wide
Enforced by CDPHE

3. Reg. 7 Revisions - Outcome
Expansion of several non-attainment area requirements statewide
Low bleed or intermittent bleed pneumatics
Control of storage tank emissions at lower thresholds
New requirements not previously included in Section XII
Definition of ‘hydrocarbon’ includes methane/ethane
Leak detection and repair (LDAR) requirements
Audio, visual, olfactory (AVO) checks
Well unloading and maintenance
Storage tank emission management (STEM)

4. STEM Overview
Purpose: Develop a Plan(s) to meet the storage tank “without venting” requirements.
Required for storage tanks with VOC emissions > 6tpy (rolling 12-month uncontrolled actuals)
NOT required for storage tanks containing stabilized liquids or tanks controlled during the first 90 days of production
Implementation of STEM Plan
Construction Date
Compliance Date
On or after May 1, 2014
Within 90 days of commencing tank operation
Prior to May 1, 2014
May 1, 2015
Increase in VOC emissions to > 6 tpy
Within 60 days of discovering increase

5. STEM Plan (XVII.C.2.b.(i)) Selected control technologies
Monitoring practices
Operational practices and/or other strategies
Procedures for evaluating ongoing storage tank emission capture performance
Monitoring with “Approved Instrument Monitoring Method” (AIMM)
Specific implementation schedule for AIMM
Certification by the owner or operator that the STEM strategies are designed to minimize emissions from storage tanks and associated equipment
Additional requirements in Statement of Basis and Purpose

6. AIMM Frequency – new tanks
AIMM is a defined term in the rule
Tanks constructed on or after May 1, 2014
VOC Emissions (tpy)
Initial Monitoring
Subsequent Monitoring
> 6tpy
Within 90 days of commencing operation
> 6 and < 12 --
Annual
> 12 and < 50
Quarterly
> 50
Monthly

7. AIMM Frequency – new tanks
AIMM is a defined term in the rule
Tanks constructed on or after May 1, 2014
VOC Emissions (tpy)
Initial Monitoring
Subsequent Monitoring
> 6tpy
Within 90 days of commencing operation
> 6 and < 12 --
Annual
> 12 and < 50
Quarterly
> 50
Monthly

8. Recordkeeping (XVII.C.3)
STEM Plan, updates, and certification
Records of monitoring (kept for 2 years)
Tank AIRS ID
Date and duration of any period of thief hatch, prv, or other access point venting (except as allowed)
Date and duration of periods when control equipment is not operating
Timing of and efforts made to eliminate venting, restore operation of control equipment, and mitigate visible emissions
List of equipment associated with tank that is designated as unsafe, difficult, or inaccessible to monitor – including explanation of designation and monitoring plan