Holdfast Vessel Works Submit a spec
A stainless jacketed reactor with an agitator drive, standing on three legs in a dark studio

Pressure vessels · Process equipment · Skids

Built for what
goes inside.

Tanks, pressure vessels, heat exchangers and complete skids. Engineered, built, tested and delivered by one shop.

Submit your equipment spec Request a vessel review

Move over the vessel to look inside

  • ASME U · U2 · RCode stamps
  • 16 ft Ø · 150 tLargest single vessel
  • CS → TitaniumMaterials we weld
  • 100%Hydrotested before it ships

01What we do

One shop.
Every step.

  1. We size it, calculate it to code and draw it.

    • Process & mechanical design
    • Material selection
    • ASME calcs & FEA
    • 3D model + drawings for your OK

  2. Rolled, welded and finished under one roof.

    • Custom vessel fabrication
    • Mixing systems
    • Heating & cooling jackets
    • Polished, passivated or painted

  3. Piped, wired and mounted. Ready to connect.

    • Piping & valves
    • Instruments & controls
    • Complete skid systems

  4. Inspected, pressure-tested and documented.

    • Weld inspection: RT, UT, PT
    • Hydrostatic test
    • Data book & full traceability

02What we build

Equipment, sorted by
what it does.

Pick a job. Filter by your industry.

03Straight answers

Four questions
every buyer asks.

  1. Q1Can you build it this big, in this metal?Yes. Up to 16 ft wide and 150 tons, in carbon steel through titanium.
  2. Q2Who handles design?We do. Or we build to your drawings.
  3. Q3What testing is included?Weld inspection, hydrotest and a full data book. On every vessel.
  4. Q4Can you deliver a complete assembly?Yes. Piped, wired, tested on one skid, and planned into your plant.

Q1 · Size & material

Will it fit our shop?
Try your size.

Volume—
Empty weight, approx.—
    Diameter
    up to 16 ft
    Length
    up to 120 ft
    Weight
    up to 150 t
    Wall
    up to 3 in
    Pressure
    full vacuum → 3,000 psi
    Temperature
    −320 → 1,000 °F

    Pick the metal by
    what's inside it.

    Not sure? Tell us the process fluid, pressure and temperature. We'll recommend the metal and show you why.

    Q2 · Design

    Who handles design?
    We do. Or we build to yours.

    Send us your process conditions. We do the sizing, code calcs and drawings. You approve, then we build.

      Unusual conditions?
      That's the job.

      • Full vacuumStiffening rings sized so the shell can't collapse.
      • Cryogenic, to −320 °FImpact-tested steels and weld procedures.
      • Hot chloridesDuplex or titanium, not 316L.
      • Sour gas, H₂SNACE MR0175 materials with hardness testing.
      • Cycling pressure & heatFatigue analysis to ASME VIII Div. 2.
      • Tight headroomLow-profile heads, side-entry agitators, split designs.

      Q3 · Inspection & testing

      What testing is included?
      All of it. On paper.

      0psi

      Hydrotested to 1.3× design pressure.

      Every vessel is filled with water, taken past its design pressure and held. If the gauge drops, it doesn't ship.

      1. FillWater, vented
      2. Raiseto 195 psi
      3. Hold30 min
      4. ResultZero drop · Pass

      On every vessel

      • Material certs (MTRs) for every plate, pipe and forging
      • Positive material ID (PMI) on alloy parts
      • Qualified weld procedures and welders
      • Visual and dimensional inspection
      • Radiography or ultrasonic testing, as the code requires
      • Hydrostatic or pneumatic pressure test
      • ASME data report and stamped nameplate

      When you need it

      • Helium leak test
      • Ferrite and hardness testing
      • Surface finish (Ra) reports
      • Post-weld heat treatment charts
      • Factory acceptance test with your team
      • Third-party or client inspector hold points

      Every weld
      has a name.

      Each seam is mapped to the welder, the procedure, the material heat number and its test result. Point at a weld.

      You get the data book.

      Digital and printed, indexed by tag number. It's everything an inspector or your insurer will ask for.

      See a sample data book
      ASME U-1AManufacturer's data report
      MTRsMaterial test reports
      Weld mapWelders · WPS · PQR
      NDERT · UT · PT reports
      Hydro chartTest record, signed
      DrawingsAs-built, Rev. final

      Code authorizations & scope

      • UASME Section VIII, Div. 1Pressure vessels, shop and field.
      • U2ASME Section VIII, Div. 2Design-by-analysis vessels, high pressure and cyclic service.
      • RNational Board RRepairs and alterations to stamped vessels, in shop or on site.
      • NBNational Board registrationEvery stamped vessel registered.
      • CRNCanadian registrationDesigns registered for all provinces.
      • PEDEU Pressure Equipment DirectiveThrough our notified body, for EU destinations.
      • ISOISO 9001:2015Quality system, audited yearly.

      Certificate numbers and scope letters are available on request.

      Q4 · Integrated assemblies

      A complete assembly?
      Yes. On one skid.

      1. FrameWelded, leveled, lifting lugs rated.
      2. VesselSet, shimmed and bolted down.
      3. PumpsAligned on their own bases.
      4. PipingSpooled, welded and tested.
      5. ControlsInstruments wired to a tested panel.
      6. FATRun with water, with you watching.

      Made to fit the plant
      you already have.

      1. We measure. Doors, headroom, pipe racks and floor loads, surveyed or laser-scanned.
      2. We model the fit. Clearances, lift points and service access, checked in 3D.
      3. We match your connections. Nozzle orientation, flange ratings and tie-ins set to your lines.
      4. We deliver and set it. Road permits, rigging plan, placed on your pad.

      04The shop

      Inside the shop.

      • 0sq ft under crane
      • 0bridge cranes, two of them
      • 0plate we can roll, 12 ft wide
      • 0stress-relief furnace
      Fabrication bay with a stainless vessel shell on turning rolls and a vessel hanging from an overhead crane
      Main bayTwo 60-ton cranes, 400 ft long.
      Plate rolling machine forming a thick steel plate into a vessel shell
      RollingPlate to 3 in thick.
      Welder running a circumferential seam on a large vessel with sparks
      WeldingQualified procedures for every alloy.
      Technician ultrasonic-testing a weld seam
      InspectionRT, UT, PT and PMI in-house.
      Pressure gauge and chart recorder during a hydrostatic test
      Hydro bayTest to 1.3× design, recorded.
      Skid-mounted process system with tank, pumps, piping and control panel
      AssemblySkids piped, wired and FAT-tested.
      Large vessel on a trailer leaving the shop at dawn
      ShippingPermits, escorts and rigging handled.

      05Start here

      Tell us what it
      needs to hold.

      An engineer, not a sales rep, answers within one business day. Budget pricing within a week.

      Concept page: nothing is sent.

      Concept site by Figured Media. Not a real business.