Oil and gas plants buy two things from a mechanical contractor: code piping that will hold a difficult fluid, and water systems that keep the plant running. Paul Industries works the downstream and plant side of this industry: ASME B31.3 process piping, tanks, heat exchangers, rotating equipment, plant utilities, and industrial water treatment including the pretreatment and polishing stages of produced water treatment. We are not an upstream oilfield services company, a drilling contractor or a midstream pigging specialist, and this page says where that line falls.
Where a plant mechanical contractor fits, and where it does not
Upstream is wells and wellsite separation. Midstream is transmission pipeline, compression and terminals. Downstream refining and the petrochemical plants behind it are process plants: vessels, exchangers, pumps, towers, tankage, utilities and thousands of feet of alloy and carbon steel piping. Paul belongs in the third category. An operator looking for an oil and gas piping contractor for a refinery unit, a utility tie-in or a water treatment building is asking for work we do. One looking for wellsite construction, downhole services or a proprietary produced water skid is asking for a different scope, and we say so rather than stretch a bid.
ASME B31.3 process piping compared with B31.1 and ASME BPE
The process piping oil and gas plants run is governed by ASME B31.3, not by B31.1 power piping and not by the hygienic rules of ASME BPE. These are not graded versions of each other; each classifies risk, examination and surface condition differently.
| Item | ASME B31.3 process | ASME B31.1 power | ASME BPE hygienic |
|---|---|---|---|
| Risk classification | Fluid service: Category D, normal, Category M for toxic fluids, high pressure, severe cyclic | No fluid service categories; by function and pressure | By product contact and cleanability |
| Girth weld examination | 5 percent random radiography in normal service; 100 percent for high pressure and severe cyclic; visual for Category D | Prescribed coverage for boiler external piping | Visual on all, plus inside borescope |
| Traceability | Mill certificates with heat numbers plus alloy verification | Mill certificates within code limits | Sulfur held from 0.005 to 0.017 percent for orbital welded 316L |
| Dead legs | Not a code concern | Not a code concern | Length to diameter ratio of 2 or less, not the legacy six diameter rule |
Fluid service drives cost: the same spool in Category D and in severe cyclic service is the same steel at a very different price, because examination, documentation and repair rates differ. See process piping and sanitary process piping.
Welding, examination and positive material identification
Welding is performed under a procedure specification qualified to ASME Section IX, by welders holding a current performance qualification for that procedure, material, thickness and position. Examination follows the code and the owner specification: visual on every accessible weld, radiography at the percentage the fluid service calls for, selected to represent every welder rather than the easiest shots, then a hydrostatic test. Each weld carries a number tying it to an isometric, a welder, a procedure and a heat number.
Positive material identification matters more here than in most industries. Alloy piping exists because the service attacks carbon steel: high temperature sulfidation, hydrogen service, acid corrosion. A carbon steel elbow in a chrome moly line looks identical once painted and insulated, and fails years later at the one component nobody verified. PMI by X-ray fluorescence or optical emission confirms the alloy in the field, with API RP 578 the usual reference.
Produced water treatment, frac water treatment and boiler feedwater treatment are three different problems
The expensive surprises in oil and gas water treatment come from treating three streams as one. They share nothing but the word water.
| Stream | What makes it difficult | Typical train | Paul scope versus vendor scope |
|---|---|---|---|
| Produced water | Free and emulsified oil, high and variable dissolved solids, scaling ions | De-oiling, solids removal to the micron range the next stage needs, then softening or desalination | We install tanks, piping, pumps, filtration and tie-ins; separators, treaters and desalination units come from vendors |
| Frac flowback | Very high and fast changing solids, friction reducer residue, barium and strontium scaling | Solids removal and conditioning, usually to a reuse specification for the next completion | Same split: we install the fixed assets; mobile units and chemistry come from their specialist |
| Boiler feedwater and makeup | Hardness, silica, alkalinity and dissolved oxygen, which scale or corrode a boiler | Filtration, softening or reverse osmosis, deionization where polish is needed, then deaeration | Our own scope: we design, install, commission and maintain these |
That is the honest version of what many produced water treatment companies present as one offering. The produced water treatment technologies a site ends up with are set by the disposal or reuse target: de-oiling alone for disposal well injection, de-oiling plus softening for reuse in a completion, full desalination only for discharge. Oilfield produced water treatment at the wellsite is mobile equipment run by a service company; plant side handling is fixed infrastructure, and that is what we build. Produced water treatment in oil and gas industry practice is two markets sharing a name.
Cooling tower water treatment and boiler chemistry in a plant setting
Every refinery and gas plant runs a cooling tower and a steam system, and both come down to the same arithmetic. Cycles of concentration is the ratio of dissolved solids in the circulating water to the makeup, set by blowdown under a conductivity controller only as good as its probe. Higher cycles save water and chemical and push toward the point where calcium carbonate, calcium sulfate or silica scales a bundle; lower cycles waste water. A tower also holds warm oxygenated water over carbon steel and copper alloys, so inhibitor and biological control never stop. The equipment and controls behind that program are set out on our cooling tower water treatment page.
Boilers have the opposite problem: oxygen is stripped in the deaerator then scavenged chemically, and hardness must leave the feedwater before it arrives, because scale on a boiler tube insulates the surface with the highest heat flux. Boiler feedwater treatment is pretreatment plus deaeration plus chemistry, and the pretreatment is the mechanical scope. Paul installs and maintains makeup treatment, side stream filtration, pumps, chemical feed skids and condensate return under plant utilities and high purity water systems. The chemical program stays with the owner’s supplier.
Corrosion in process plants, and the real limits of passivation
Three mechanisms account for much of the unplanned work here. Chloride stress corrosion cracking attacks austenitic stainless such as 304 and 316 where tensile stress, chlorides and elevated temperature occur together, producing branching cracks that leak with no general thinning, so a thickness survey will not find it. Corrosion under insulation attacks carbon steel from the outside and, with chloride bearing wet insulation, cracks stainless from the outside in, hidden under cladding wherever insulation stays damp. Under deposit and erosion corrosion attack the inside where solids settle or velocity concentrates wear.
Passivation is often sold as the answer to all three, and it is not. It removes free iron and restores the chromium rich passive layer, valuable after fabrication, after contamination and at commissioning. It does not close an existing crack, does not reverse pitting that has penetrated, does not slow erosion and does nothing for carbon steel. Where the mechanism is cracking or wall loss, the remedy is assessment and repair; passivation and derouging come afterward.
Tanks and exchangers: API 650, API 653 and retubing
Atmospheric storage tanks are built to API 650 and maintained under API 653, which covers inspection, repair, alteration and reconstruction of tanks in service. An api 650 tank is a new build question; API 653 governs what you may do to a tank you already own, and its inspections are performed by API authorized inspectors. Paul fabricates and installs tanks and performs mechanical repair and modification on existing tankage, but we do not hold or issue API certifications, and a job needing a certified inspector gets one named in the scope.
Heat exchanger retubing replaces individual tubes or a whole bundle once fouling, thinning or leaks make a unit unreliable. The choice between retubing, re-bundling and replacement turns on shell condition, tube material and remaining service life. Pulling a bundle, plugging to a documented limit, retubing and reinstalling to the original tube sheet layout is millwright and rigging work with a code hydrotest at the end. See heat exchangers.
Refinery turnaround services and shutdown support
A turnaround is a scheduling problem wearing a mechanical costume. The scope is known months ahead; what decides whether it finishes is how much left the critical path before the unit came down. Refinery turnaround services worth buying start with prefabrication: spools built and examined in the shop, where welds are in position and radiography is not competing for scaffold time, so field work reduces to tie-ins and testing.
The sequence that works: a frozen scope with a cutoff date, isometrics and weld maps issued before mobilization, shop fabrication and examination complete before the outage, blind and isolation lists agreed with operations, tie-ins in a planned order with test packs defined in advance, then hydrotest, reinstatement and turnover as the unit restarts. Late additions are the largest cause of overrun. See shutdown and turnaround services.
What to require from an oil and gas piping contractor
The difference between bidders is invisible in a price sheet and visible in five documents. Ask before award, not after a failed radiograph.
| Requirement | Evidence to ask for | Why it matters |
|---|---|---|
| Code qualification | Procedure and qualification records for the actual materials and thicknesses, plus current welder qualifications | A procedure qualified on something else is not qualified |
| Examination plan | A written plan tied to fluid service, naming percentage, selection method and NDE provider | Stops the easiest welds being the only ones shot |
| Material control | Mill certificates with heat numbers, a PMI plan where alloys are involved | Alloy mix-ups surface years later, in service |
| Turnover package | A sample from a finished job: isometrics, weld map and log, NDE and PMI records | A contractor who cannot show one has never produced one |
| Scope honesty | A written statement of what is subcontracted and to whom | Water packages and certified inspection are usually someone else |
The same list works for a refinery piping contractor, for an industrial piping contractor on a gas plant utility job and for an industrial water treatment company bidding the treatment building.
What Paul Industries does
We fabricate and install process piping in carbon steel and stainless to ASME B31.3, by orbital and manual welding under procedures qualified to ASME Section IX. We build process and storage tanks, overhaul heat exchangers and chillers, set pumps and rotating equipment, provide millwright and rigging, and maintain plant utilities including steam, chilled water and compressed air. We design, install and service industrial water treatment including reverse osmosis, deionization, softening and filtration, plus wastewater and effluent pretreatment. We perform passivation, derouging and corrosion remediation, mechanical integrity assessment, turnaround support, preventive maintenance, commissioning and engineering and design. Our pipe fabrication services cover shop spool fabrication and field erection, which is what we mean by oil and gas fabrication.
What we are not: an upstream oilfield services company, a drilling contractor, a midstream pipeline or pigging specialist, a manufacturer of separators, treaters or packaged produced water units, or an API authorized inspection firm. Where a project needs those, we work alongside the firms that do. To scope a job use request a quote, or see industries.
Standards referenced: ASME B31.3 · ASME BPVC · ASTM A967 · ASTM A380 · NFPA 30 · 40 CFR 403
Frequently asked questions
Does Paul Industries work in oil and gas?
Yes, on the downstream and plant side. That means ASME B31.3 process piping in refineries, gas processing and petrochemical plants, process and storage tanks, heat exchangers, pumps, plant utilities, water and wastewater systems, corrosion remediation and turnaround support. It does not mean wellsite construction, drilling services or midstream pipeline work, which are different scopes with different equipment and different crews.
What is produced water treatment?
Produced water treatment is the conditioning of water that comes out of a well with the oil or gas so it can be reused, discharged or injected. The train normally starts with de-oiling, then solids removal, then softening or desalination depending on the target. Paul installs the tanks, piping, pumps, filtration and tie-ins; the process packages themselves come from their vendors.
How does produced water treatment in oil and gas industry settings differ from municipal water treatment?
Municipal plants treat a reasonably predictable feed to a published drinking or discharge standard. Produced water varies enormously in salinity, oil content and scaling potential between fields and over the life of a well, and the target is often reuse or injection rather than discharge. The result is more pretreatment, more chemistry and far less standardization in equipment selection.
What are the main produced water treatment technologies?
The usual stages are gravity and enhanced de-oiling, gas flotation, media or cartridge filtration for solids, chemical or ion exchange softening to remove scaling hardness, and desalination by membrane or thermal process where salt has to be removed. Which produced water treatment technologies apply depends on the reuse or disposal target, not on the water alone.
How should I compare produced water treatment companies?
Separate the two roles first. Process technology vendors own the separation and desalination packages and the performance guarantee that goes with them. Mechanical contractors own the tanks, piping, pumps, structures, utilities and installation. Most produced water treatment companies sell one of those and subcontract the other, so ask which half a bidder actually performs with its own crews.
What is frac water treatment and how is it different?
Frac water treatment handles flowback from a completion, which arrives with very high and quickly changing solids, residual friction reducer and strong scaling potential from barium and strontium. It is usually treated to a reuse specification for the next completion rather than to a discharge standard, and it is often done with mobile equipment at the pad rather than fixed plant.
Do frac water treatment companies also install the tanks and piping?
Sometimes, but the two scopes are usually split. Frac water treatment companies bring the treatment equipment, the chemistry and the operators. Fixed tankage, transfer piping, pump stations, containment and utility connections are construction work. Paul performs that construction side on plant and facility installations; mobile wellsite spreads are not our scope.
Is oilfield produced water treatment at the wellsite something Paul does?
No. Oilfield produced water treatment at the wellsite is mobile, operated equipment run by upstream service companies, and we are not one of them. Our water work is fixed plant: treatment buildings, makeup and feedwater systems, reverse osmosis and deionization, softening, filtration and effluent pretreatment, with the piping, tanks and pumps that go with them.
What code applies to the process piping oil and gas plants use?
ASME B31.3 covers process piping in refineries, gas plants and chemical plants. It classifies lines by fluid service, including Category D for low hazard service, normal fluid service, Category M for toxic fluids, high pressure and severe cyclic conditions, and each category sets its own examination requirements. B31.1 applies to power and boiler external piping instead, and ASME BPE governs hygienic product contact tube.
What should a refinery piping contractor prove before award?
Six things: welding procedure and welder qualifications covering the actual materials and thicknesses, a written examination plan tied to fluid service, material traceability with a PMI plan where alloys are involved, prefabrication capacity, a sample turnover package from a finished job, and a written statement of what is subcontracted. Price differences between bidders usually trace back to one of those.
What are refinery turnaround services and which part can Paul take?
Turnaround services are the mechanical work executed in a planned unit outage: line replacement, tie-ins, exchanger and tank work, equipment overhaul and reinstatement. Paul provides shop prefabrication ahead of the window, field installation crews, millwright and rigging, water and utility system work, testing and turnover documentation. Process licensors, catalyst handling and certified inspection remain with their specialists.
Is Paul a fabricator or an installer?
Both, and that is the point. Our pipe fabrication services cover shop spool fabrication from isometrics with weld maps and examination records, and our field crews erect, tie in, test and commission the same work. One accountability for the weld, the examination and the installation is what we mean by oil and gas fabrication, rather than fabricating and handing a problem to someone else.
What is boiler feedwater treatment and why does it matter in a plant?
Boiler feedwater treatment removes hardness, silica, alkalinity and dissolved oxygen before water reaches a fired surface. Scale on a boiler tube is an insulating layer where heat flux is highest, and oxygen pits the steel. The answer is pretreatment by softening, reverse osmosis or deionization, mechanical deaeration, then chemical conditioning. The pretreatment and the mechanical equipment are our scope.
Why is cooling tower water treatment a mechanical scope as well as a chemical one?
Because the chemistry only works if the equipment does. Cooling tower water treatment depends on cycles of concentration held by a conductivity controller on blowdown, on side stream filtration that actually removes solids, on working chemical feed pumps and on clean basins. Paul installs and maintains that equipment and piping; the inhibitor and biocide program is normally run by the owner's chemical supplier.
Does Paul build an api 650 tank, and what is API 653?
Paul fabricates and installs process and storage tanks and performs mechanical repair and modification of existing tankage. API 650 is the standard for new welded atmospheric storage tanks; API 653 governs inspection, repair, alteration and reconstruction of tanks already in service, with inspections performed by API authorized inspectors. We do not hold or issue API certifications, and a job needing a certified inspector gets one named in the scope.
What is heat exchanger retubing and when is it worth doing?
Heat exchanger retubing replaces the tubes or the whole bundle in a shell and tube unit when fouling, thinning or leaks have made it unreliable. It is worth doing when the shell, tube sheets and nozzles are sound and the unit has years of service left. When the shell is suspect or the service has changed, replacement or a different tube material usually wins on total cost.
When does passivation help a stainless system in this service, and when does it not?
Passivation removes free iron and restores the passive chromium oxide layer, so it helps after fabrication, after iron contamination and at commissioning. It does not close chloride stress corrosion cracks, does not reverse existing pitting, does not slow erosion corrosion and does nothing for carbon steel. Where the mechanism is cracking or wall loss, the fix is assessment and repair, with passivation afterward.
How do I choose an industrial water treatment company for a plant rather than a wellsite?
Ask what the company installs with its own people and what it buys in. A plant water system is construction: tanks, piping, pumps, skids, controls and commissioning, with a treatment package inside it. An industrial water treatment company that only sells equipment still needs a mechanical contractor, and one that only installs still needs the process guarantee. Know which you are buying.
Related: Industries We Serve · Process Piping · Process & Storage Tank Installation · Sanitary Heat Exchanger Installation & Service · Process Wastewater, Effluent & Chemical Sanitization · Plant Shutdowns & Turnarounds · Request a quote