TDG Sections 1.51 and 1.52: What Changed?

Two New TDG Special Cases: Water Pump System Tanks, Engines and Machinery

Transport Canada’s June 2026 amendment to the Transportation of Dangerous Goods Regulations (TDGR), SOR/2026-112, introduced a significant number of changes intended to improve international harmonization and modernize Canada’s dangerous goods requirements.

These changes include two entirely new special cases in Part 1 of the TDGR: Section 1.51 – Water Pump System Tank and Section 1.52 – Engines and Machinery. Although these provisions apply to very specific situations, they can provide substantial regulatory relief when all of their conditions are met.

New Special Case 1.51 – Water Pump System Tank

Section 1.51 addresses certain water pump system tanks containing low-pressure compressed gas.

Water pump system tanks are commonly used in water systems to maintain system pressure and reduce cycling of pumps. Because these tanks may contain compressed air or another compressed gas, they may fall within the TDG Regulations even though transporting compressed gas is not the equipment’s primary purpose.

Which Compressed Gases Qualify?

Under the current TDGR, Parts 3 to 6, 8 and 17 do not apply to the importing, offering for transport, handling or transporting of the following dangerous goods when all of the conditions of Section 1.51 are met:

UN1002, AIR, COMPRESSED
UN1046, HELIUM, COMPRESSED
UN1066, NITROGEN, COMPRESSED

This means qualifying shipments receive relief from several significant TDG requirements, including documentation, dangerous goods safety marks, means of containment, training, reporting, and site registration.

What Conditions Must Be Met?

This is not a blanket exemption for compressed gas tanks.

To qualify, the compressed gas must be contained in a water pump system tank and must not be intended to be discharged from that tank.

The tank itself must meet several requirements. It must be designed, manufactured, tested and marked in accordance with ANSI/WSC PST, and it must be filled, closed, secured and maintained so that there is no release of dangerous goods that could endanger public safety under normal conditions of transport, including handling.

The tank must also:

Be made of steel or composite material;
Have ends that are concave to pressure;
Have a maximum outside diameter of 660.4 mm;
Contain gas at a pressure of no more than 280 kPa at 20°C when filled for transport; and
Be packed in a strong outer packaging.

That last point is important. Simply having a qualifying water pump pressure tank does not automatically trigger the exemption. The packaging and construction conditions must also be satisfied.

Why Does This Special Case Matter?

The change provides a practical approach for equipment that contains a relatively low-pressure compressed gas.

Without the special case, these articles could be subject to TDG requirements designed primarily for conventional compressed gas transportation even though the compressed gas is an integral part of the equipment and is not intended to be released during transport.

For companies manufacturing, distributing or returning water pump system tanks, Section 1.51 could therefore significantly simplify transportation — provided every condition of the exemption is documented and satisfied.

Part 17 – Site Registration Relief

SOR/2026-112 originally exempted qualifying water pump system tanks from Parts 3 to 6 and 8. Shortly afterward, the Canadian Update published in July 2026, SOR/2026-127, amended Section 1.51 to also specifically exempt qualifying shipments from Part 17 – Site Registration Requirements.

This clarification reflects Transport Canada’s position that, except for Section 1.16, Part 1 special cases are intended to provide relief from the Part 17 site registration requirements when their conditions are met.

New Special Case 1.52 – Engines and Machinery

The second new provision, Section 1.52, deals with dangerous goods associated with engines and machinery. This is potentially much broader in application.

Modern machinery can contain numerous dangerous goods necessary for its operation. Depending on the equipment, that might include fuel, batteries, fire extinguishers, compressed gases or other regulated components.

Section 1.52 establishes a Canadian special case for engines and machinery meeting the conditions of Special Provision 154.

Under subsection 1.52(1), the TDG Regulations — except Parts 1, 2 and 4 — do not apply to an engine or piece of machinery that meets the conditions of Special Provision 154 and is transported under a UN number to which that special provision applies.

In other words, classification and safety-mark requirements remain relevant, but the other Parts of the TDGR provide substantial relief.

What Marking Requirements Still Apply?

However, a very specific marking requirement remains.

Despite the normal requirements of Part 4, two opposite sides of each engine or piece of machinery must display either:

Option 1

The UN number and a placard for the primary class.

Option 2

The UN number and shipping name and a label for the primary class.

Companies shipping large machinery should pay particular attention to the requirement for the information to appear on two opposite sides of the engine or machinery.

What About Other Dangerous Goods Installed in the Machinery?

Section 1.52 goes a step further.

Dangerous goods other than fuel may also be installed in the engine or machinery and receive additional regulatory relief when they are:

Required for the functioning or safe operation of the engine or machinery;
Required for the safety of its operator; and
Securely installed in the engine or machinery.

When those conditions are satisfied, and the engine or machinery is on a road vehicle, railway vehicle or vessel, the TDGR, except for Parts 1 and 2, do not apply to those dangerous goods.

Notice the important distinction: this portion of the exemption specifically excludes fuel.

Special Relief for Prototype Lithium Batteries

Section 1.52 also addresses an interesting issue involving prototype lithium batteries.

Normally, lithium cells and batteries are subject to testing requirements before transport. However, subsection 1.52(3) provides specific relief from the condition in paragraph 2.43.1(2)(a) for lithium cells and batteries that are:

Pre-production prototypes transported for testing; and
Part of a production run of 100 or fewer cells or batteries.

This provision may be particularly useful for manufacturers and developers transporting prototype equipment containing lithium batteries during product development and testing.

What Do These New TDG Special Cases Mean for Shippers?

Sections 1.51 and 1.52 are good examples of Transport Canada taking a more practical approach to dangerous goods that are incorporated into equipment rather than being transported as conventional dangerous goods packages.

For water pump system tanks, the new rules recognize that certain low-pressure compressed gases can be transported safely without applying the full TDG framework when strict construction, pressure and packaging conditions are met.

The exemptions can reduce unnecessary regulatory burden — but only when every condition is met.

Before You Rely on These Special Cases

Before using either special case, shippers should review the current TDG Regulations, the applicable special provisions and the characteristics of the equipment being transported. When in doubt, document the analysis before the shipment moves.

Questions about the new TDG special cases? Contact ICC The Compliance Center for guidance on the latest regulatory requirements and how they may apply to your shipments.