Paul Industries fabricates and installs process piping across Oklahoma, including work on plants that were designed when nobody in this state thought about earthquakes. Oklahoma’s induced seismicity rate has fallen substantially since its peak, largely because of regulatory action on wastewater injection, and it has not returned to what it was before 2009. A great deal of industrial equipment in the state predates the question entirely, and flexible connections and proper anchorage are inexpensive insurance that most of it does not have.
Request a quote or call 201-450-8280
A hazard that arrived, was reduced, and did not leave
Oklahoma’s earthquake rate rose dramatically from around 2009, driven by the disposal of produced water by deep injection, and the state’s response was regulatory rather than passive. In 2015 the Oklahoma Corporation Commission directed that wells injecting into the lower portion of the Arbuckle Group be backfilled with cement so that injection was limited to shallower levels, alongside reductions in injected volume.
The intervention worked. Research on the effect indicates that seismicity rates in recent years are substantially lower than they would have been without those plug-backs, and reducing injection depth in particular has been identified as an effective lever, with implications for other regions facing the same issue.
The honest engineering reading of that is neither alarming nor dismissive. The hazard is materially lower than it was at its peak. It is also higher than it was before the phenomenon began, and the relevant question for a plant is not whether a damaging earthquake is likely but whether the consequences of a moderate one are acceptable.
For a process plant, those consequences are rarely structural. Buildings in the state are generally robust enough for the shaking involved. What fails is the equipment inside them and the connections between things that move differently.
What actually breaks, and what it costs
| Vulnerability | Consequence | Remedy |
|---|---|---|
| Unanchored tanks and vessels | Sliding or rocking; connections torn off | Anchorage designed for lateral load |
| Rigid pipe between separately supported items | Differential movement breaks the pipe | Flexible connection at the interface |
| Pipe crossing a building joint | Two structures moving independently | Expansion or flexible arrangement at the joint |
| Heavy items on unbraced supports | Support collapse | Lateral bracing to the structure |
| Suspended services | Swinging; impact with adjacent services | Sway bracing and clearance |
| Chemical storage without restraint | Spill compounding the incident | Restraint plus containment |
The second row is the one that produces most of the damage and it is the least intuitive. A tank sitting on a slab and a pump bolted to a separate plinth will move differently during shaking. A rigid pipe joining them has to accommodate that difference, and it cannot, so it fails at its weakest point, which is usually a nozzle on the vessel. The vessel is then damaged and its contents are released, which turns a minor event into a serious one.
A flexible connection at that interface costs very little, is installed in an afternoon, and removes the failure mode entirely. On a plant handling anything hazardous, hot or in large volume, it is among the best-value protective measures available, and the reason it is so often absent is simply that nobody asked the question when the plant was built.
The same logic applies wherever a pipe crosses from one structure to another, or from a building into the ground, and those locations are identifiable in a walk round with a drawing.
| Continuous load | Per year | Over ten years |
|---|---|---|
| 15 kW | $7,674 | $76,740 |
| 30 kW | $15,348 | $153,480 |
| 60 kW | $30,696 | $306,960 |
Oklahoma has among the cheapest industrial electricity in the country at 5.84 cents per kilowatt-hour, 0.72 times the 8.13 cent national average (EIA, 2024). That is a genuine operating advantage for energy-intensive processing, and it is worth mentioning here because it is part of why capacity continues to be built in the state, which in turn means new plants are being designed now, with the opportunity to get anchorage and flexibility right at no incremental cost.
A proportionate approach
We would not recommend a full seismic retrofit program to most Oklahoma process plants, and it is worth saying so plainly. What we recommend is a walk-round assessment that identifies the small number of items where a moderate event would produce a disproportionate consequence, and addressing those.
The screening questions are simple. Which vessels hold something whose release would be a serious event, and are they anchored? Where does rigid pipe connect items with separate foundations? Does anything heavy sit on a support with no lateral bracing? Where do services cross a building joint? Is chemical storage restrained?
That assessment is a day’s work on most plants and it produces a short list. The items on it are typically cheap to fix, and they are the ones where the difference between a plant that shrugs off an event and one that has a serious incident is a few hundred dollars of bracket and bellows.
Our piping work follows ASME B31.3 with the fluid service category determined and documented, and B31.5 where refrigeration piping is in scope. Sanitary and high-purity systems are built to ASME BPE with orbital welding to AWS D18.1, weld documentation retained, verified slope and drainability, and passivation to ASTM A967 after cleaning per ASTM A380. Where seismic design provisions apply to a specific installation, we coordinate with the structural engineer of record rather than substituting for one.
Standards referenced: EIA electricity price data · ASME BPE · ASME B31.3 · ASTM A967 · ASTM A380
Frequently asked questions
Do you install process piping in Oklahoma?
Yes, across Oklahoma City, Tulsa, Lawton, Enid and statewide: sanitary and high-purity piping, process and utility systems, tank and vessel connections, flexible connections and anchorage, pressure testing and the documentation package.
Are Oklahoma earthquakes still a concern?
A reduced one. Rates fell substantially after the Corporation Commission’s 2015 directive requiring wells injecting into the lower Arbuckle to be backfilled with cement, alongside volume reductions, and research indicates recent seismicity would be considerably higher without those measures. The hazard is lower than at its peak and higher than before 2009.
What actually fails in a process plant?
Rarely the building. What fails is equipment inside it and the connections between items that move differently: unanchored vessels, rigid pipe between separately supported items, unbraced supports under heavy equipment, and suspended services with no sway bracing.
Why is rigid pipe between separate foundations a problem?
Because a tank on a slab and a pump on its own plinth move differently during shaking, and a rigid pipe joining them cannot accommodate that difference. It fails at its weakest point, usually a vessel nozzle, which damages the vessel and releases its contents.
What is the best-value protective measure?
A flexible connection where rigid pipe crosses between separately supported items. It costs very little, installs in an afternoon, and removes the failure mode entirely. On a plant handling anything hazardous, hot or in large volume, it is hard to beat for value.
Do we need a full seismic retrofit?
Almost certainly not, and we would say so. What is worth doing is a walk-round assessment identifying the small number of items where a moderate event would produce a disproportionate consequence, and addressing those. It is usually a day’s work and a short list.
What does that assessment look for?
Which vessels hold something whose release would be serious and whether they are anchored; where rigid pipe connects items with separate foundations; whether anything heavy sits on unbraced supports; where services cross building joints; and whether chemical storage is restrained.
Should new plants design for this?
Yes, and at essentially no incremental cost. Anchorage and flexible connections decided at design stage are a specification detail rather than a retrofit, which is the argument for settling them now on any new Oklahoma capacity rather than adding them later at many times the price.
Why is so much capacity being built in Oklahoma?
Energy cost is a substantial part of it. Oklahoma industrial electricity averages 5.84 cents per kilowatt-hour, 0.72 times the 8.13 cent national average (EIA, 2024), which is a real operating advantage for energy-intensive processing.
How do I get a quote for an Oklahoma piping project?
Use the form on this page or call 201-450-8280. Useful inputs are line sizes and materials, which ASME B31.3 fluid service category applies, the vessels and equipment involved and how they are founded, and whether a seismic walk-round is wanted alongside the main scope.
What seismic design category applies to Oklahoma sites?
The category assigned by the building code from the site's mapped ground motion and soil class, which the revised hazard maps have raised for central Oklahoma, setting the bracing and anchorage requirements for piping and equipment. The category is determined for each site rather than assumed for the state.
How is suspended piping inside a building braced for seismic loads?
With lateral and longitudinal braces at intervals set by the pipe size and the design category, attached to the structure rather than to other services, and with flexible connections where the pipe crosses building joints. Unbraced suspended piping swings and breaks at its connections.
What is inspected after a seismic event?
Equipment anchorage, flexible connections, pipe supports and braces, flanged joints and instrument connections, with leak checks on hazardous services before restart. A post-event inspection procedure is written before the event.
What automatic protection responds to a tremor?
Seismic switches that trip gas supply, shut down hazardous processes or close isolation valves when ground motion exceeds a threshold, so that a release does not depend on an operator's response. They are fitted where the consequence of a leak justifies the occasional spurious trip.
How is produced water handled at the piping level?
Produced water from oil and gas operations is saline, sometimes contains hydrocarbons and hydrogen sulfide, and is corrosive; its piping is designed for the chemistry with corrosion-resistant materials or linings. Handling it at surface rather than injecting it is part of the seismicity response.
What about produced water treatment and reuse?
Treatment for reuse in completions or for surface discharge involves desalination and hydrocarbon removal, with piping and equipment for saline, corrosive streams. It is a growing engineering area in the state.
How does thermal movement affect Oklahoma outdoor piping?
Oklahoma's temperature range is wide, and outdoor stainless and carbon steel runs move materially, so expansion provision and support design account for it alongside seismic flexibility. The two requirements are compatible.
What materials suit Oklahoma's hard, saline water in piping?
Corrosion-resistant materials for lines carrying brine and concentrate from water treatment, and attention to scaling in hard water lines. The water treatment concentrate is the most aggressive stream on many sites.
How are pipe racks braced?
With lateral bracing designed for the code's seismic and wind loads, anchored to foundations, and with guides that allow thermal movement while restraining lateral. Racks built without lateral bracing are common on older sites.
How is a retrofit prioritised?
By consequence: connections to hazardous inventory first, then critical utilities, then general process piping. The assessment produces a ranked list and the retrofit follows it within budget.
What sectors are building in Oklahoma?
Food and supplement processing, aerospace, energy-related manufacturing and data infrastructure, drawn by cost and location. The piping work spans sanitary, utility and process disciplines.
How does induced seismicity interact with process safety management?
A seismic event is a credible initiating event for covered processes, and the process hazard analysis should consider it and the plant's response. Flexible connections and anchorage are the mitigations it usually recommends.
What about tanks and vessels?
Tall, unanchored tanks and vessels are the highest-risk items in a tremor, and their anchorage and the flexibility of their connected piping are assessed first. Tank connections are where releases occur.
How is seismic flexibility added to existing piping?
With flexible connectors or expansion joints at equipment nozzles, revised support and anchor arrangements, and in some cases rerouting to add natural flexibility. It is done during planned outages.
What is the commonest seismic finding in Oklahoma plants?
Rigid pipe connecting equipment on separate foundations with no flexibility and no anchorage, installed decades before anyone considered the question. It is cheap to fix and expensive to ignore.
The other side of the same story: handling produced water
The injection that drove Oklahoma’s seismicity is the disposal end of a stream the state produces in enormous volume, and handling that stream is a piping discipline in its own right. It is also one where the industry’s direction of travel has changed: reducing injection volumes means finding something else to do with the water, which means treating it, which means process equipment.
Produced water is a difficult fluid and each of its properties drives a different design decision.
It is extremely saline. Salinity far above seawater is common, which puts it squarely into the chloride problem described on our chloride cracking page. Austenitic stainless is frequently the wrong choice, and the alternatives are higher alloys, appropriate non-metallics, or internally lined carbon steel depending on temperature, pressure and cost. Specifying 316 because it is the default stainless is how these systems fail early.
It carries solids and scale-formers. Sand and formation fines abrade, and dissolved barium, strontium, calcium and iron precipitate as conditions change. A line that scales internally loses capacity gradually, and scale in a produced water system can be difficult to remove and occasionally carries naturally occurring radioactive material concentrated by the process, which turns a cleaning task into a regulated one.
It carries hydrocarbon. Residual oil affects treatment selection, fouls membranes and separators, and determines what the water can be used for afterwards.
It may be sour. Where hydrogen sulphide is present, materials selection changes fundamentally and so does the safety case, because the gas is acutely toxic at low concentrations and heavier than air. That is a design consideration for pits, sumps and low-lying enclosed spaces rather than only for the piping.
The treatment trains being built around this stream range from simple separation and filtration for reuse in further operations, through desalination for broader reuse, to concentration and crystallization where the aim is to minimize the volume requiring disposal. Each is a process plant with the fouling, scaling and materials problems above, and each is being built against an economic case that improves as disposal becomes more constrained.
We fabricate and install produced water handling and treatment piping, working to ASME B31.3 with the fluid service category determined and documented, with materials selected against the actual water analysis rather than a generic specification. Where a client has an analysis and a temperature, we would rather start there than with a material preference.
Piping or anchorage questions at an Oklahoma plant?
Ask us to include a seismic walk-round with the main scope. It is a day’s work and it usually produces a short, cheap list. Call 201-450-8280 or use the form below.