CRN Registration for Packaged Skids and Modular Process Units: The Complete Canadian Guide

By Kopfkino Consulting Corp. · Published September 14, 2026 · Updated October 17, 2026 · 12 min read

Most provinces issue no single skid CRN. A packaged skid is decomposed into vessel CRNs, fitting CRNs and a piping design registration. This guide maps every route across Canada.

In most Canadian jurisdictions there is no single "skid CRN." A packaged skid is decomposed into its pressure-boundary components: each pressure vessel gets its own CRN, every fitting (CSA B51 categories A-H) needs a CRN or documented exemption, and the interconnecting piping requires a piping design registration. Saskatchewan has a dedicated skid program; Ontario offers PSTD; Alberta registers per installation.

If you build, sell, or specify packaged process equipment for Canadian projects (metering skids, pressure-reduction packages, compressor units, filtration modules, fuel-gas trains) you have been asked: "Does the skid have a CRN?" The question sounds simple; it is not, because Canada does not register skids as such. It registers the designs of boilers, pressure vessels, fittings, and pressure piping systems under provincial law, with CSA B51 as the national framework. That mismatch (an integrated commercial package versus a component-by-component legal regime) is where most schedule overruns and stranded skids originate.

Why there is no single "skid CRN"

A Canadian Registration Number (CRN) confirms that the design of a specific boiler, pressure vessel, fitting, or pressure piping system has been reviewed and accepted by the provincial authority having jurisdiction (AHJ), a design registration, not a product certification. Because "skid" is a fabrication concept rather than a regulatory one, a package registers as the sum of its parts:

• Pressure vessels: separators, filters, scrubbers, pulsation bottles, air receivers. Each distinct vessel design needs its own CRN, built to ASME BPVC Section VIII; one registered design covers unlimited identical units built anywhere in the world.
• Fittings: every pressure-boundary component except the pipe itself, sorted by CSA B51 Table 1 into categories: A pipe fittings (tees, elbows, reducers); B flanges; C valves; D expansion joints and hose assemblies; E strainers, filters, separators, steam traps; F measuring devices (gauges, transmitters); G capacity-certified pressure relief devices; H components not covered by A-G (plus category N for nuclear). Each fitting on the skid needs a CRN or a documented jurisdiction-specific exemption.
• Pressure piping: the interconnecting pipe spools. The system design is registered from P&IDs, line lists, piping specs, GA drawings, and design/stress calculations, to ASME B31.1, B31.3, or B31.5.

A typical skid therefore carries one vessel CRN, a dozen fitting CRNs, and one piping registration, per destination jurisdiction. The registration trigger is generally pressure above 15 psi (≈103 kPa); exemption from registration is never exemption from the governing Act or code.

The Category H small-assembly route

CSA B51 Table 1, Note 2(b) contains one genuine shortcut: an assembly of components (including piping components) in which no component exceeds 152 mm (6 in) diameter and total volume is ≤ 42.5 L (1.5 ft³) can register as a single Category H fitting, the key route for compact instrument, analyzer, and metering-run packages. Above those limits the assembly decomposes as above; small items below 152 mm ID or 42.5 L that are vessels in their own right are likewise classed as Category H fittings under the CSA B51 Figure 1(a)-(c) pressure-volume logic.

How each jurisdiction handles skids

The decomposition principle is Canada-wide; the mechanics differ by AHJ, and a CRN from one jurisdiction is not automatically valid in another.

Saskatchewan: the dedicated skid program

TSASK's Information Paper IP-2016-07-04 is the most explicit skid regime in Canada: a skid (a metal plate or frame pallet mounting pressure piping and/or pressure equipment) registers as a separate pressure piping design:

• A unique skid design registration number is referenced in future registrations; identical repeat skids are not re-reviewed.
• The 0.5 m³ aggregate-volume exemption does not apply to registered skid designs.
• Registration expires 10 years from registration; no design changes without TSASK approval.
• Every fabricated skid carries a nameplate with manufacturer name, serial number, and skid design registration number.
• Registered skids must be stand-alone for overpressure protection, no inter-connected PRD common discharge headers between skids or with distribution piping.
• Drawings and line lists must be stamped by a Saskatchewan-licensed P.Eng.; a TSK-1002 Construction Data Report is completed per fabricated skid.

Fees (as of the July 2024 schedule) are $225 registration plus review at $155/hr (minimum 2 h); standard turnaround is about six weeks. Confirm current fees with TSASK.

British Columbia: the >NPS 3 skid piping directive

Technical Safety BC's piping directive requires that piping systems greater than NPS 3 on skid packages be registered to the applicable ASME B31 code before construction begins (BC Reg. 104/2004 s. 84(5)); piping NPS 3 or less is exempt from registration under s. 84(3) but remains subject to the code. BC also exempts standard Category A, B, C and G fittings (directive D-BP-2013-03), reducing (but not eliminating) the fitting-CRN burden inside a BC-bound skid.

Alberta: installation-specific, non-transferable skid registrations

ABSA has no skid design program analogous to TSASK's. Piping registers per installation via Form AB-96 (sealed by an Alberta P.Eng.), and an Alberta skid registration is tied to one installation and non-transferable. Three rules matter to packagers:

• The 0.5 m³ rule is system-aggregate (PESR s. 14(6)(a)): piping over 500 L total internal capacity (expansible fluid, above 103 kPa) must be registered, measured for the system, not per skid. Splitting a plant into sub-500 L skids to evade registration is not permitted.
• All pressure piping fabricated outside Alberta must be registered regardless of volume.
• Alberta has no categorical fitting exemption; A, B, C and G fittings all need CRNs, unlike BC, Saskatchewan and Manitoba.

Ontario: P-numbers and PSTD

TSSA registers piping designs as site-specific P-numbers or P-standard (PSTD) numbers for repeatable designs, the closest Ontario analogue to a repeatable skid registration. Drawings must identify construction code, fluid service, design and test conditions, PRV settings, and attest that only registered fittings are used. Vessels ≤ 42.5 L or ≤ 152 mm ID are exempt (O. Reg. 220/01 s. 2(2)(q),(r)); boiler/vessel designs must bear an Ontario P.Eng. authentication (s. 4(3)).

Quebec and the rest of Canada

In Quebec, the RBQ registers vessel, boiler and fitting designs; piping registration occurs when the installer files a declaration of installation at least 30 days before work completion (r. 6.1 s. 32), the number issued becoming the piping registration number. For NB, NS, PE, NL, YT, NT and NU, ACI Central performs the reviews, one submission can cover all seven member jurisdictions.

Jurisdiction comparison for skid packages

Equipment-type snapshots

Metering skids. Small-bore piping, meters, transmitters (Category F), control valves (Category C), condensate pots (often Category H). Compact metering runs frequently qualify for the Category H small-assembly route; custody-transfer stations with filter/separator vessels do not.

Pressure-reduction skids. Predominantly a piping-registration problem: regulators, slam-shuts, and relief valves (Category G, requiring ASME capacity certification) inside a registered piping design. Saskatchewan's stand-alone overpressure-protection rule applies directly to PRS packages.

Compressor packages. The compressor, driver, and components integral to rotating machinery whose primary stresses derive from functional requirements are excluded (AB PEEO s. 2(2)(j); ON O. Reg. 220/01 s. 2(2)(m)). Scrubbers, coolers, pulsation bottles, and piping on the same skid are not covered by the exclusion.

Filtration skids. Classification hinges on size: a small cartridge filter may be a Category E fitting, while a large separator is a registered ASME VIII vessel.

Fuel-gas skids. Components must be mapped across the CSA B51/CSA B149 boundary: downstream of the gas meter/regulator, fuel-gas installation codes generally govern; upstream conditioning (heaters, separators, filters) stays in the pressure-equipment regime. Fired-heater pressure coils are expressly "fittings" in Alberta.

Modular process units / multi-skid plants. Each module decomposes as above; aggregation rules (Alberta's 0.5 m³ system rule, TSASK's multi-package guidance) prevent threshold gaming. Plan registration at plant level, execute per module.

Worked example: decomposing a gas metering skid

Consider a natural-gas metering skid for an Alberta site, fabricated in Ontario: an inlet filter/separator vessel (ASME VIII, 400 mm ID), an NPS 4 meter run, two control valves, a transmitter and gauge, a relief valve, NPS 2-4 interconnecting piping, and a small condensate pot (100 mm, 20 L).

• Filter/separator vessel: vessel CRN; in Ontario, drawings sealed by a PEO-licensed P.Eng. (s. 4(3)). One design registration covers identical units.
• Control valves: Category C fitting CRNs (no categorical exemption in Alberta or Ontario).
• Transmitter and gauge: Category F CRNs (or proof of the instrument OEM's existing registrations).
• Relief valve: Category G CRN with ASME/NB capacity certification.
• Condensate pot: under 152 mm and 42.5 L, registered as a Category H fitting.
• Interconnecting piping, fabricated outside Alberta, so AB-96 registration is required regardless of volume, authenticated by an Alberta P.Eng.

Net result for one skid in Alberta: 1 vessel CRN + 4-6 fitting CRNs + 1 piping registration. Repeat per destination province, using the 2020 RCT Reconciliation Agreement's reciprocal mechanism (nine participants; Alberta excepted) and ACI Central's seven-jurisdiction review to minimize duplicate reviews.

Timeline and procurement implications

Design registration happens before construction: in BC by law (s. 84(5)), in Ontario at the applicant's risk, and by practical necessity everywhere else, because retrofitting compliance is expensive or impossible. Planning numbers (as of current regulator publications; confirm with the AHJ): TSASK ~6 weeks standard; TSBC ~20-30 business days for initial review, with 2×/3.5× expedited tiers; TSSA publishes no SLA (industry reports 6-16 weeks; unanswered queries close the application after 21 calendar days); ABSA reviews hourly with a priority option (+30%, minimum $490.50).

For procurement, CRN scope must be settled at RFQ stage: every fitting on the bill of materials needs a CRN (or documented exemption) for the destination provinces before fabrication release. One unregistered valve can hold up the entire package at inspection or commissioning.

Common mistakes

• Assuming one CRN covers the skid. There is no umbrella skid CRN in most jurisdictions; the package is only as compliant as its weakest component.
• Unregistered fittings nested in skids. Ontario requires an attestation that only registered fittings are used; TSASK cross-checks line lists. One non-CRN valve can sink the whole submission.
• Assuming A/B/C/G fitting exemptions apply Canada-wide. True in BC, Saskatchewan, Manitoba (and partially Quebec), false in Alberta, Ontario, and the ACI jurisdictions.
• Splitting systems to dodge the 0.5 m³ threshold. Alberta aggregates volume at the system level; TSASK's skid program carries no volume exemption.
• Assuming an Alberta skid CRN travels. Alberta piping/skid registrations are installation-specific and non-transferable.
• Connecting PRD discharge headers across skids. TSASK-registered skids must be stand-alone for overpressure protection.
• Late inspection-agency engagement for offshore fabrication. AHJ-accepted inspection must be arranged before fabrication; BC calls retroactive registration "contrary to the safety regulation and... very expensive/burdensome or impossible."
• Forgetting fitting CRN expiry. Fitting registrations expire 10 years after first acceptance; a component CRN can lapse mid-project.

Best practices

(Engineering recommendations, not regulatory requirements; confirm current requirements with the AHJ of destination.)

• Decompose at design freeze. Build a component-by-component registration matrix (vessel / fitting category / piping) per destination jurisdiction before releasing drawings.
• Buy CRN'd components. Source valves, transmitters, PRDs and fittings already registered in your target provinces; verify the designator digits after the decimal (e.g., "2" or "C" for Alberta use).
• Exploit Category H where legitimate. Keep compact instrument assemblies within 152 mm / 42.5 L to register once as a single fitting.
• Pick a strong first jurisdiction, then use RCT reciprocal routes and ACI Central for breadth; run ABSA in parallel: Alberta never piggybacks.
• Design repeatable packages to the strictest destination. If one product line serves Canada, design to Alberta/Ontario expectations plus Saskatchewan's stand-alone PRD geometry from the start.
• Track expiries centrally. A renewal calendar for all component fitting CRNs prevents mid-project lapses.

Frequently Asked Questions

Does a whole skid get one CRN, or does each component need its own?

In most jurisdictions, each component: one CRN per vessel design, one per fitting (or documented exemption), plus a piping design registration. Saskatchewan's skid program is the main exception, but the vessels and fittings inside still follow the normal rules.

Is there a "skid CRN" anywhere in Canada?

Saskatchewan issues dedicated skid design numbers under IP-2016-07-04, and Ontario's PSTD numbers function as repeatable standard-piping registrations. Alberta skid registrations exist but are installation-specific. None eliminates component-level vessel and fitting CRNs.

Does skid-mounted piping need registration in British Columbia?

Yes, if greater than NPS 3: TSBC requires design registration to the applicable ASME B31 code before construction begins. Piping NPS 3 or less is exempt from registration under BC Reg. 104/2004 s. 84(3) but must still comply with the code.

Can I register a skid once and use it across multiple provinces?

Component CRNs can be extended province by province: nine jurisdictions participate in the RCT Reconciliation Agreement, and ACI Central covers seven Atlantic/northern jurisdictions with one review. Alberta always requires a separate ABSA review, and its piping registrations are installation-specific.

What is the Category H small-assembly route?

CSA B51 Table 1, Note 2(b) lets an assembly in which no component exceeds 152 mm diameter and total volume is ≤ 42.5 L register as a single Category H fitting, ideal for compact metering, analyzer, and instrument packages, but not stretchable to larger skids.

Does my skid's piping need registration in Alberta even if it is very small?

Yes, if fabricated outside Alberta: all out-of-province fabricated pressure piping must be registered with ABSA regardless of volume. In-province, the threshold is a >0.5 m³ aggregate system volume for expansible fluids above 103 kPa.

Do the relief valves on my skid need CRNs?

Yes. Relief devices are Category G fittings, and primary overpressure-protection devices must hold ASME certificates of authorization. Alberta and Ontario register Category G without exemption; BC, Saskatchewan and Manitoba exempt ASME/NB-stamped PRDs.

How long does skid registration take?

Component registrations drive the schedule: published figures include ~6 weeks at TSASK and ~20-30 business days for TSBC initial reviews; TSSA publishes no SLA (industry reports 6-16 weeks). Timelines are as of current regulator publications: start before fabrication.

Key Takeaways

• There is no single "skid CRN" in most of Canada: skids decompose into vessel CRNs, fitting CRNs (CSA B51 categories A-H), and a piping design registration.
• Saskatchewan (IP-2016-07-04) offers a dedicated, repeatable skid registration; Ontario offers PSTD; Alberta registers per installation, non-transferably.
• Alberta registers all out-of-province fabricated piping regardless of volume and aggregates the 0.5 m³ exemption at the system level.
• BC requires registration of skid piping greater than NPS 3; BC/SK/MB fitting exemptions do not extend to AB/ON/ACI jurisdictions.
• Compact assemblies ≤ 152 mm / ≤ 42.5 L can register once as a single Category H fitting.
• Registration precedes fabrication; unregistered fittings inside a package are the most common (and most avoidable) failure mode.

Related Guides

• Does My Skid Need a CRN? A Decision Guide for Equipment Bound for Canada
• One CRN per Skid or per Component? How Regulators Decompose Packaged Equipment
• CRN for Metering Skids: Registering Piping, Instruments and Vessels in One Package
• CRN for Pressure-Reduction Skids: Piping Design Registration Essentials
• Fuel-Gas Skids and the CSA B51/B149 Boundary: Which Components Need a CRN?
• Compressor Packages and the Machinery Exclusion: What Still Needs a CRN on a Compressor Skid
• CRN for manifolds and skids
• CRN for piping systems: overview
• CRN for fittings: overview
• Skid Packages: When a System Triggers Multiple CRNs and How to Scope Them
• Skid Package CRN Strategy for Canada

Sources

• CSA B51, Boiler, Pressure Vessel, and Pressure Piping Code (B51:24): https://www.csagroup.org/store/product/2701790/
• TSASK IP-2016-07-04, Application for the Registration of a Skid Design: https://api.tsask.ca/wp-content/uploads/2024/07/IP-2016-07-04_-_Application_for_the_Registration_of_a_Skid_Design.pdf
• Technical Safety BC, Directive: Inspection Requirements for Piping Systems and Piping Components: https://www.technicalsafetybc.ca/regulatory-resources/regulatory-notices/directive-inspection-requirements-piping-systems-and-piping-components
• BC Reg. 104/2004: https://www.bclaws.gov.bc.ca/civix/document/id/complete/statreg/104_2004
• ABSA, Design Registration: https://www.absa.ca/design-registration/
• Ontario O. Reg. 220/01 (Boilers and Pressure Vessels): https://www.ontario.ca/laws/regulation/010220
• TSSA, Guidelines for Registration of Pressure Piping (Jan 2025): https://www.tssa.org/sites/default/files/2025-02/Guidelines%20for%20Registration%20of%20Pressure%20Piping-BPV-Jan10,2025-Guidelines.pdf
• TSSA, Fitting Registration Guidelines (Jan 2026, Rev 3): https://www.tssa.org/downloads/fittings-guidelines-jan-2026-rev-3
• RBQ, Regulation respecting pressure installations (c. B-1.1, r. 6.1): https://legisquebec.gouv.qc.ca/en/ShowDoc/cr/B-1.1,%20r.%206.1
• RCT, Reconciliation Agreement for the CRN for Pressure Equipment (2020): https://rct-tccr.ca/agreement/canadian-registration-number-crn-pressure-equipment/
• ACI Central: https://www.acicrn.com/

Decomposing a packaged skid into registerable components (and sequencing registrations across up to 13 jurisdictions) is where experienced support prevents costly rework. Kopfkino Consulting assists package suppliers, OEMs and EPCs with CRN applicability assessments, registration strategy, design review before fabrication, code calculations, submission packages, P.Eng. coordination where provincial authentication is required, multi-province registration through the RCT agreement and ACI Central, regulator-comment resolution, and dedicated support for international manufacturers entering Canada. Contact us early in the design phase to scope what must be registered, where, and in what order.

Topics: CRN Registration, Skid Packages, Modular Process Units, Packaged Equipment