Peak vibration velocity at the poker head typically lands in the 1.0 to 3.0 mm/s range for most site pokers in the 28 to 60 mm diameter class, with frequency spanning 8,000 to 16,000 vibrations per minute (vpm) depending on drive type and head size [S4][S6].
The actual mm/s figure at the concrete interface is set by the eccentric mass, its offset radius, and rotational speed, and it is heavily damped by the surrounding wet concrete within a few centimetres of the head, so a handheld vibration meter reading is dominated by head geometry and not by slump [S2][S3].
What sets the mm/s reading: amplitude, frequency and head mass
Vibration velocity (mm/s RMS or peak) is the product of amplitude (mm) and angular frequency (rad/s), so a 2 mm amplitude at 12,000 vpm yields a different velocity than the same amplitude at 9,000 vpm, which is why amplitude and frequency must be read together, not alone [S3].
Manufacturer and engineering sources describe two clear clusters: smaller heads (25 to 38 mm) run higher vpm (12,000 to 16,000) at lower amplitude, while larger heads (45 to 100 mm) run lower vpm (8,000 to 12,000) at higher amplitude, producing comparable vibration velocities at the head wall but a much larger radius of action [S3][S4][S5]. For a typical site poker in the 38 to 45 mm range, expect roughly 1.5 to 2.5 mm/s peak at the casing; an Excalibur-spec 25 mm needle is published at 12,000 to 16,000 vpm, and a Controls C0163/D petrol poker at 8,000 vpm with a 25 x 320 mm head [S4][S6]. Lievers' battery P18Li with a 28 mm head is rated around 12,000 vpm on the same drive unit that also accepts 38 and 45 mm heads [S1].
Head diameter versus radius of action: the practical comparison
Choosing a poker is rarely about maximising mm/s; it is about matching head diameter to element thickness, rebar spacing, and the radius of action you need per insertion [S1][S3]. As a rule of thumb, head diameter should be about a quarter of the wall thickness for the cast element, and a single insertion consolidates a roughly circular zone from around 45 cm across for a small head up to about 85 cm for a large one on Lievers' LHF-E electric range [S1][S5].
Four practical size bands line up as follows, drawn from the cited guides: (1) 25 to 28 mm, for thin walls, columns, kerbs, and heavily reinforced precast, with a 45 cm action radius and 12,000 to 16,000 vpm; (2) 38 to 45 mm, the everyday structural range for walls, slabs, ground beams, and most foundations, with action radius around 50 to 70 cm; (3) 45 to 60 mm, for deeper beams and thicker rafts, with action radius up to about 80 cm; (4) 60 to 100 mm, for mass pours, large footings, and high-volume placing, with action radius up to about 85 cm or more [S1][S3][S4]. For concrete poker sizing on a 60 m3/hour pour, see the spec-driven count in Poker Vibrator Count for a 60 m3/Hour Pour: Spec-Driven Sizing, which applies the same diameter-to-action-radius logic at plant scale.
Power source and how it shifts the velocity reading
The drive unit changes the vpm band, which in turn shifts the velocity at the head, even when amplitude is held constant. Electric high-frequency pokers fed from a 200 Hz converter sit at the top of the vpm range (12,000 to 16,000 vpm) and are favoured on civil-infrastructure pours longer than 6 m, where long flexible shafts would otherwise sap amplitude [S1][S3][S4].
Cordless battery pokers such as the Lievers P18Li deliver around 12,000 vpm from an 18 V lithium-ion pack, trading continuous-run endurance for site mobility where no mains is available [S1]. Petrol and diesel pokers (e.g. Controls C0163/D at 8,000 vpm) give mobility and torque for remote pours but run at the lower end of the vpm range, and pneumatic pokers are common in mining and hazardous-area work because the air motor is intrinsically safe [S4][S6]. As a concrete vibration analyzer would show on a controlled test pad, switching from an 8,000 vpm petrol drive to a 12,000 vpm electric drive on the same 38 mm head typically raises head-wall velocity by 30 to 50 percent, because velocity scales linearly with frequency at fixed amplitude.
What mm/s figure you should actually expect on site
Hand-arm vibration exposure at the grip is a different quantity from head velocity, and operators are limited by the daily A(8) exposure action value under hand-arm vibration regulations, not by what the head is doing inside the concrete [S1][S5]. Bigger and more powerful heads transmit more vibration to the operator, so a heavier 60 mm poker that consolidates 0.5 m3 per plunge is only a win if the crew can legally run it for the full shift.
Two practical rules are stable across the cited sources. First, space insertion points at roughly 6 to 10 times the head diameter (commonly around 50 cm for a typical site poker) so the action zones overlap, otherwise uncompacted concrete is left between plunges and shows up as honeycombing [S1][S3]. Second, hold each insertion for about 5 to 15 seconds, until the surface sheen stabilises and bubbles stop breaking out; pulling out too early or dragging the head through the mix is the most common cause of voids, sand streaks, and mortar channels, per the Precast.org field guide [S4][S5].
Measurement caveats: why published mm/s numbers vary
Manufacturers rarely publish a single head mm/s figure because the reading depends on the transducer mount, concrete stiffness, and how close the sensor sits to the eccentric. A vibration sensor clamped to the poker casing a few centimetres above the head will read meaningfully higher than one embedded 10 cm into the mix, and a stiffer low-slump concrete damps the reading faster than a high-slump one [S2][S3].
This is why spec-driven selection should rest on diameter, frequency, and action radius, then verify on site with a vibration meter on the first insertion of the pour rather than relying on a single catalogue number. For a concrete vibrator selection tied to a specific element thickness and rebar layout, the diameter-to-wall-thickness rule and the 6-10x spacing rule do most of the work, and the mm/s value is the verification number rather than the design input.
Two trackable signals to watch through 2026: tighter EN 60745-2-12 hand-arm vibration declarations on cordless poker data plates, and a push by precast plants to publish action-radius-versus-diameter tables as a standard selection aid rather than as marketing copy.