An LDAR monitoring plan is the central document that ties a leak detection program together. It defines what is regulated, how leaks are identified and repaired, who is responsible, and how the program is documented. A solid plan satisfies inspectors, protects the facility against enforcement risk, and gives field technicians a clear playbook. This guide walks through the seven steps to build one from scratch — or to bring an existing plan up to current expectations under NSPS OOOOa, NSPS OOOOb, refinery NESHAP, and state programs.
What Goes Wrong Without a Plan
Step 1 — Identify Applicable Regulations
Federal Rules
Determine which federal LDAR standards apply by source category and construction or modification date. Common federal triggers include:
- 40 CFR 60 Subpart OOOOa — oil and gas sources constructed or modified after September 18, 2015.
- 40 CFR 60 Subpart OOOOb — oil and gas sources constructed, modified, or reconstructed after December 6, 2022.
- 40 CFR 60 Subpart VV/VVa — SOCMI process unit equipment leaks.
- 40 CFR 61 Subpart V — equipment leaks of designated NESHAP pollutants.
- 40 CFR 63 Subpart CC — petroleum refinery NESHAP.
- 40 CFR 63 Subpart FFFF — miscellaneous organic chemical manufacturing MACT.
- 40 CFR 264/265 Subpart BB — equipment leaks at hazardous waste TSDFs.
State and Local Rules
State programs frequently add requirements on top of federal rules. Examples include Colorado Regulation 7, Pennsylvania GP-5 and GP-5A, Texas oil and gas standard permits, and California air district rules. Confirm with the state air agency and any operating permits before assuming federal-only applicability.
Operating Permits and Consent Decrees
Title V permits, NSR/PSD construction permits, and any active consent decrees can each contain LDAR conditions that go beyond the underlying NSPS or NESHAP. Pull and review every active permit and decree before drafting the plan.
Step 2 — Inventory Affected Equipment and Components
Walk down every covered process unit and tag every potentially leaking component. Each tag should have a unique ID, location, equipment type, service classification, and the applicable rule citation.
Component Types to Capture
- Valves (manual block, control, plug, ball, gate)
- Connectors and flanges
- Pumps and compressors (seals)
- Pressure relief devices and rupture disks
- Open-ended lines
- Sampling connection systems
- Agitator seals
- Storage tank thief hatches and PRVs
Service Classifications
Most rules differentiate by service:
- Gas / vapor service — component contains a gas or vapor at process conditions.
- Light liquid service — vapor pressure greater than 0.3 kPa at 20°C and the substance is liquid at process conditions.
- Heavy liquid service — everything else (typically less rigorous monitoring).
Service classification controls the monitoring frequency and the applicable threshold, so it must be assigned correctly at tagging time.
Step 3 — Determine Monitoring Frequencies
Each rule sets its own frequencies. Common patterns:
Standard Frequencies
- Valves in gas/light liquid service: commonly monthly to quarterly under legacy rules; semiannual or quarterly under NSPS OOOOa/OOOOb depending on source.
- Connectors: typically annual.
- Pumps: weekly visual + monthly Method 21 in many programs.
- Pressure relief devices: after each release event, plus periodic monitoring.
- OGI fugitive surveys (oil and gas): semiannual at well sites and quarterly at compressor stations under OOOOa, with OOOOb tightening several of these intervals.
Step 4 — Define Leak Thresholds and Methods
Method Selection
Document which detection methods will be used — EPA Method 21, OGI cameras, AVO inspections, or some combination — and which method applies to which component category. If using OGI under the Alternative Work Practice at 40 CFR 60.18, the plan must spell out the camera model, training requirements, and operating procedures.
Leak Definition
State the ppm threshold (or "any visible emissions" for OGI) for every component category. Include the calibration gas, response factor, and instrument used. Inspectors will compare what is in the plan to what is recorded in the field; mismatches are red flags.
Step 5 — Set Up Recordkeeping
Records to Maintain
- The current written monitoring plan and all revisions
- Component inventory with tag IDs, locations, and service classifications
- Monitoring schedule and completed monitoring events
- Instrument and camera calibration records
- Individual ppm readings and OGI video files
- Leaks identified, including tag, date, time, technician, reading
- Repair attempts (first attempt within 5 days, final repair within 15 days under most rules) and any delay-of-repair justifications
- Re-inspection results confirming the leak was fixed
- Personnel training records and refresher cycles
- Annual or semiannual reports submitted to EPA or the state
Step 6 — Establish Repair and Re-Inspection Workflows
Standard Repair Timing
Most rules require a first attempt at repair within 5 days of leak identification and final repair within 15 days. Delay of repair is permitted only when repair is technically infeasible without a unit shutdown; the delay must be documented and the component placed on a delay-of-repair list.
Re-Inspection
After repair, the component must be re-monitored to confirm the leak is below the applicable threshold. Re-inspection results become part of the permanent record for that component.
Step 7 — Train Personnel
Even the best-written plan fails if technicians, supervisors, and contractors are not trained on it. Document initial training, periodic refreshers, and any competency demonstrations (especially for OGI operators, where image interpretation skill drift is well-documented). See our LDAR Training Guide for a deeper look at building the training program.
Common Pitfalls to Avoid
Ecesis Software Solutions for LDAR
LDAR Software
Component inventories, monitoring schedules, leak tracking, and regulatory reports.
Compliance Obligations
Centralize federal, state, and permit-driven LDAR obligations with assignable owners.
Document Management
Version-controlled storage for the monitoring plan, permits, and calibration records.
Preventive Maintenance
Auto-generated work orders for leak repairs and re-inspection deadlines.
Training Management
Track LDAR and OGI operator certifications, refreshers, and competency records.
Management of Change
Keep the component inventory current as equipment is added, modified, or retired.
