Modular & Small-Scale Refineries

PSM Compliance for Modular & Small-Scale Refineries: A Field Guide

Modular refineries face the same OSHA PSM obligations as their larger counterparts — but without the institutional knowledge, legacy documentation systems, or dedicated safety staffing. Here’s what you actually need to know.

Does OSHA PSM Apply to Your Modular Refinery?

This is the first question, and the answer surprises many new operators. OSHA’s Process Safety Management standard (29 CFR 1910.119) applies based on the quantities of highly hazardous chemicals present at your facility — not based on your facility’s size, output capacity, or whether you self-identify as a “small” operation. If you process flammable hydrocarbons at or above threshold quantities, PSM applies. Period.

For petroleum refineries, PSM coverage is essentially universal — crude oil and its derivatives are listed as flammable liquids under Appendix A at a threshold of 10,000 pounds. A modular crude oil fractionation unit, a small stripping column, a produced water treatment system with flammable hydrocarbon contact — these are all potentially PSM-covered regardless of how many barrels per day they process.

PSM Applicability: Key Thresholds

Chemical / Category	Threshold Quantity	Relevant for Modular Refineries?
Flammable liquids / gases (Appendix A)	10,000 lbs	Yes — crude oil, condensate, LPG, naphtha
Hydrogen sulfide (H2S)	1,500 lbs	Yes — sour crude processing, amine units
Flammable gas (e.g., propane)	10,000 lbs	Yes — fuel gas systems, LPG storage
Hydrogen (H2)	10,000 lbs	Yes — hydrotreating units

The Documentation Challenge for New Builds

Large refineries built in the 1950s through 1980s have decades of accumulated PSM documentation — original design packages, accumulated inspection records, PHA histories, and procedure libraries developed and refined over multiple turnaround cycles. New modular builds start from zero. That’s both a challenge and, if handled correctly, an opportunity.

The PSM documentation package you need to have in place before you introduce highly hazardous chemicals to your process includes:

• Process Safety Information (PSI). Maximum intended inventories, design basis for all pressure vessels, piping, and relief systems, equipment specifications, and P&IDs that are accurate to as-built conditions. For modular units, this means obtaining complete documentation from your equipment vendor and verifying it against actual field conditions during installation.
• Process Hazard Analysis (PHA). A completed PHA (typically HAZOP for modular refinery configurations) must be completed before you introduce HHCs. You cannot commission a PSM-covered unit without a signed, complete PHA on file.
• Operating Procedures. Written procedures for startup, normal operation, emergency shutdown, and abnormal operations — at minimum. These procedures must reference safe operating limits that match your PSI documentation.
• Pre-Startup Safety Review (PSSR). A formal PSSR must be completed and documented before initial startup. This is not a checklist exercise — it requires verifying that PSI is complete and accurate, PHA recommendations have been addressed, and procedures are in place.

Common Mistake

Many modular refinery operators assume that because their equipment was vendor-designed and factory-tested, the PSM documentation obligation is somehow reduced. It isn’t. The vendor’s documentation is a starting point — the operator bears full responsibility for maintaining a complete and current PSM program once the facility is operational.

RAGAGEP Pitfalls for Facilities Without Institutional Knowledge

Larger refineries have decades of practice applying industry standards to their specific equipment configurations. They’ve lived through multiple standard revision cycles and — even if imperfectly — have developed institutional memory about what RAGAGEP means for their facilities. Modular and small-scale refineries starting fresh don’t have that baseline.

The RAGAGEP pitfalls that most commonly catch new operators:

• Vendor documentation references are not RAGAGEP compliance. A vendor’s data sheet citing ASME Section VIII for vessel design tells you the design basis — it doesn’t constitute your ongoing RAGAGEP compliance record. You need documentation showing that your inspection, testing, and maintenance practices align with current applicable standards.
• Relief system documentation gaps. API 520/521 requirements for relief device sizing documentation, documentation of the relieving basis, and records of any changes to process conditions that might affect relief system adequacy are among the most commonly cited RAGAGEP gaps at smaller facilities.
• Electrical classification documentation. NFPA 70 (NEC) and API RP 505 requirements for documenting hazardous area classification are frequently incomplete at new builds — the drawings exist in design packages but aren’t incorporated into the PSM file in a form that satisfies RAGAGEP documentation requirements.
• Mechanical integrity frequencies. API 510 (pressure vessels), API 570 (piping), and API 653 (storage tanks) specify risk-based inspection frequencies. New facilities often have the equipment covered but lack the written inspection plan that demonstrates their inspection program aligns with these standards.

Building a PSM Program From Day One

The best time to build a PSM program is before your facility starts up, not after your first inspection notice arrives. Porritt Inc.’s Standards Modernization Sprint is specifically designed for new and recently commissioned facilities that need to establish a complete, current-edition RAGAGEP-aligned documentation library. The engagement covers standards applicability mapping, documentation gap identification, and development of the key PSM documents you need — for a fixed fee of $12,000.

If you’re already operational and have concerns about your PSM program’s current state, our Gap Assessment ($8,500) delivers a complete picture of your compliance posture and a prioritized remediation plan. Either way, you leave with documentation that can withstand scrutiny — from OSHA, from your insurers, or from the incident investigation team you never want to need.

Bottom Line

The complexity of PSM compliance does not scale down with your facility’s size. The documentation obligations, RAGAGEP requirements, and inspection expectations are the same whether you’re processing 500 barrels per day or 50,000. Build the program correctly from the beginning — it’s far cheaper than rebuilding it after an enforcement action.

Build Your PSM Program the Right Way

Whether you’re commissioning a new modular unit or catching up on an existing facility, Porritt Inc.’s Standards Modernization Sprint delivers a complete, RAGAGEP-aligned documentation foundation for a flat $12,000.

Start Your Modernization SprintCall 385-439-2478