Knuckle boom trucks (articulating cranes)

R 03 mHow a knuckle boom differs from a stiff boom

IHSA describes boom trucks as mobile cranes on a commercial truck chassis strengthened to take the crane, built in two common configurations: the telescoping boom and the articulating crane¹. The articulating crane is the knuckle boom, called a knuckle picker in the West. CSA's standard for it covers articulating boom cranes on commercial trucks or trailers, and stationary and mobile ones, that lift, swing and lower loads by an articulating boom, which may also telescope².

In law it is still a boom truck. Alberta's OHS Code defines a boom truck by a telescoping or articulating boom that can swing, hoist, or raise and lower its load³. What changes is how it is rated, the standard behind it and, in some provinces, the operator rule.

The joints let a knuckle boom place a load over a wall, under an eave or through an opening. The cost is capacity at reach, which is what its rating describes.

R 06 mTonne-metre ratings, explained

A stiff boom is sold by a ton class. A knuckle boom is often sold by its moment rating: load multiplied by the radius at which the crane can lift it. We found no Canadian public source that explains the rating, so the clearest one is foreign: as a non-Canadian reference, NT WorkSafe explains that vehicle-loading cranes are rated in metre-tonnes, the maximum chart load times its radius, with an example of 2.89 m × 4.55 t = 13.145 metre-tonnes⁵.

The trap is treating that number as a constant. In the same non-Canadian reference chart, capacity falls from 4,550 kg at 2.89 m to 730 kg at 12.55 m⁵. Load times radius stays near 13.0 to 13.5 tonne-metres out to 8.33 m, then drops to about 9.2 tonne-metres at 12.55 m⁵, because other limits take over at long reach (non-Canadian reference, derived from the chart).

Example, computed from that chart. Divide the 13.145 rating by 12.55 m and you get about 1,047 kg. The chart allows 730 kg. A lift sized from the headline rating would be more than 40% over the chart at full reach. Ask the supplier for the chart capacity at your radius, every time, and see how to read a load chart.

• Thresholds are in tonnes, not tonne-metres. Provincial operator rules use tonnes of lifting capacity, such as Alberta's 7.3 t for knuckle booms without live lines⁶. Which figure on a knuckle boom's plate or chart counts against a threshold is a question for the regulator or certifying body.
• Stability margins are not public for knuckle booms. Under CSA Z150:20, a stiff boom truck's rating on stabilizers is capped at 85% of the tipping load⁷. The matching rules in Z150.3 are not in any free preview we could read, so use the manufacturer's chart.

R 09 mThe standard: CSA Z150.3 and which provinces adopt it

CSA Z150 covers mobile cranes and excludes articulating boom cranes, pointing to CSA Z150.3 instead⁴. Z150.3 in turn leaves out cranes whose booms do not articulate, non-conductive-boom cranes and vehicle-mounted aerial devices, forestry and logging cranes, scrap handlers and concrete pumpers². The 2017 edition, reaffirmed in 2022, is the one Ontario, Saskatchewan, Nova Scotia and PEI cite; CSA's store now lists it as withdrawn, and we have not confirmed a replacement².

A standard binds only where a province adopts it, and each names an edition:

CSA Z150:26, the 2026 sixth edition of the mobile crane code, now exists⁴, but no province in our research has adopted it, and it excludes knuckle booms anyway. Other provinces are on their province pages. When a crane crosses a border, ask which standard it was built and certified to.

R 12 mCertification thresholds for articulating booms

Most provinces require a certified operator above a set capacity; here is the rule where you work. Several treat a knuckle boom differently from a stiff boom, some by whether it has a winch.

The winch keeps coming up. Alberta draws its line on "live lines", the trade profile's term (confirm how your machine is classed); Nova Scotia gives a winchless articulating boom its own licence class; SATCC's trade text describes cranes with a power drum and wire rope, and we have not confirmed how Saskatchewan treats a folding boom without one. Before a bare hire (operator not included), check the winch and the rating against your operator's certificate.

R 15 mSelf-loading delivery work

A lot of knuckle boom work is delivery: a supply truck setting drywall, block or roofing on a roof, a balcony or an upper floor. As a non-Canadian reference, Queensland's code defines a vehicle-loading crane as one mounted on a vehicle to load and unload it, and notes that larger units now also do traditional crane work such as lifting to upper floors¹⁹.

Unloading your own truck versus doing crane work matters in Canada too:

• Saskatchewan exempts a crane used exclusively to load or unload its own vehicle from the qualified-operator rule¹⁵, but a crane rated 5 tonnes or more still needs a competent operator with written proof of training¹⁵.
• Manitoba defines a boom truck hoist as a telescoping or articulating boom that can load on and off the truck, rated over 7.3 t and not over 40.8 t²⁰. Self-loading is part of the definition, not an exemption.
• Alberta, BC and Nova Scotia: the rules summarized above contain no self-loading exemption.

If the crane lifts anything other than its own load off its own deck, plan it as crane work: a certified operator where a threshold applies, a set-up clear of power lines, and a chart in the cab. Alberta's OHS Code section 63(1) requires a boom truck to carry its load charts at all times³.

R 18 mPublished hourly add-on rates

Public schedules price a knuckle boom the way it is often built: as an attachment on a truck. New Brunswick's 2026 schedule adds $8.25 an hour at 2–3 t up to $34.00 at 16–18 t to the truck rate for an articulated knuckle boom, bare (operator not included)²¹:

The same schedule charges more for a telescoping straight boom in each band, for example $11.25 at 2–3 t²¹ and $38.00 at 16–18 t²¹. It says only "add to truck rate" and does not name the truck. Its service trucks of 13,608 to 36,287 kg list at $45.50 to $60.25 an hour, bare²¹.

Example, computed from New Brunswick's 2026 rows. On the 13,608 to 20,411 kg service truck at $45.50 an hour²¹, a 6–7 t knuckle boom would make $58.50 an hour bare ($45.50 + $13.00), before the operator. New Brunswick does not say it pairs them; the example shows how an add-on works, not what a job costs.

Elsewhere, Newfoundland and Labrador's March 2024 schedule adds $15.00 an hour for a hydraulic boom up to 9 t on a stake body truck, and $22.00 over 9 t²², without saying whether it articulates. BC Wildfire Service lists deck cranes from 1.5 to 8 ton at $6.27 to $38.02 an hour, with no operator rate on the line²³.

Published rates are benchmarks for public works, not quotes. Private quotes add minimum hours, mobilization, travel and fuel. See boom truck rental rates and the rental rate converter.

R 21 mWhen a stiff boom is the better tool

A stiff boom with a winch is usually the better hire when:

• The load goes down, or high on a line. A hoist line can lower a load into a pit or vault and lift to the height the tip points at. CSA's mobile crane code is written for booms carrying tackle that can be lengthened or shortened⁴; a tip-hook knuckle boom has none.
• The load is heavy and far away. Knuckle charts fall fast with reach. Compare charts at your radius, not headline ratings.

A knuckle boom usually wins when the load has to go over a wall, under an eave or through a window, or when the truck must also carry the load. If the job is putting people at height, neither is right: Alberta's OHS Code treats a unit that positions a personnel basket or platform as an aerial device³, built to CSA C225, which both crane standards exclude⁴². See boom truck vs crane vs boom lift.

In doubt, send the load, radius and height and ask for the chart capacity at your radius for each option. The size estimator and boom reach calculator help you get those numbers first.

R 24 mRequesting a knuckle boom quote

Request a quote; it only goes to a company with your consent. For a knuckle boom, these details change the answer:

• The load's weight in kilograms and its size, with slings, forks or other rigging counted in.
• The radius from where the truck can stand to where the load lands, and the height to reach or clear.
• Whether the load must go below the truck or on a line, which needs a winch.
• Whether the truck carries the load (self-loading) or lifts something already on site.
• Obstacles between truck and landing: walls, eaves, trees and wires.
• Ground and room for the stabilizers.
• Operated (operator included) or bare (operator not included); if bare, your operator's certificate and province.
• Dates, duration and the address.

With your consent, your request goes to one company that rents, sells or finances boom trucks in your area. That company may pay BoomTrucks.ca for the referral. We do not rent, sell or lease equipment, so which crane fits is the supplier's call from its chart. Buying instead? See buying a boom truck.