How Loud Is a Floor Scrubber? dB From 17 Spec Sheets

Q: How many decibels is a floor scrubber?

Battery models are published at 52 to 75 dB(A), most walk-behinds at 65 to 70, and quiet modes at about 58 to 62. LPG and diesel sweeper-scrubbers reach 83 to 84 dB(A).

Q: Do floor scrubber operators need hearing protection?

Not for battery machines alone, which are 10 dB or more below NIOSH's 85 dBA. Operators of LPG or diesel combination machines in loud plants should have their exposure measured.

Q: Is a robotic floor scrubber quieter than a manual one?

Not necessarily. Kärcher's KIRA B 50 is listed at 69 dB(A) and Tennant's T7AMR "as low as 70 dBA", the same range as a walk-behind.

Key takeaways

Battery floor scrubbers are published at 52 to 75 dB(A), and most walk-behinds sit between 60 and 70. The only machines in our table above 80 dB(A) are LPG and diesel sweeper-scrubbers, at 83 to 84 dB(A).
Quiet or eco modes cut a walk-behind by about 5 to 9 dB. Tennant's T300 drops from 64.9 to 57.8 dBA at the operator's ear.
No battery machine in the table comes within 10 dB of NIOSH's 85 dBA limit, and none comes near OSHA's 90 dBA.
Only 4 of the 17 figures name a measurement standard, and only one names a distance. Treat a gap of 3 dB or less between two sheets as no difference.
Hospitals and schools want 30 to 35 dB in the room, which no scrubber meets, so scrub patient rooms and classrooms when they are empty. A quiet mode under 60 dB(A) is quieter than a normal speaking voice at 1 m.

A battery floor scrubber is published at about 52 to 75 dB(A), depending on its class and mode. A typical walk-behind is listed at 65 to 70 dB(A) in normal mode and around 58 to 62 dB(A) in its quiet mode. LPG and diesel sweeper-scrubbers are much louder: Nilfisk lists its SC8000 at 83 to 84 dB(A). Every battery machine in our table is at least 10 dB below the NIOSH recommended limit of 85 dBA, and well below the OSHA 90 dBA limit.

Two answers circulate: "about 60 dB, conversation level" and "70 to 85 dB, wear hearing protection". Each is true of some machines and modes. They persist side by side because most spec sheets do not say how or where the sound was measured. Of the 17 published figures below, only four name a test standard and only one gives a distance. The table sorts machines by class well. It cannot pick between two machines 3 dB apart.

Published sound levels by machine class

Each figure is the maker's own number, copied as printed, with the source's own unit. "Not stated" means the sheet gives no test standard and no microphone position.

Class	Machine (maker)	Published sound level	How it was measured, as stated
Micro walk-behind	BR 30/1 C Bp Pack (Kärcher)	55 dB(A)	Not stated
Micro rider	Stealth DRS21BT (Betco)	54 dB	Not stated (reported by HFM, 2014)
Walk-behind	B 60/10 eco (Kärcher)	52 dB	Not stated (reported by HFM, 2014)
Walk-behind	T300 (Tennant)	64.9 to 66.5 dBA by head type	Operator's ear, ISO 11201
Walk-behind, quiet mode	T300 Quiet-Mode (Tennant)	57.6 to 59.1 dBA	Operator's ear, ISO 11201
Walk-behind	SC401 43 B (Nilfisk)	65 ±3 normal, 60 ±3 silent mode	Not stated; tolerance given
Walk-behind, corded	SC401 43 E (Nilfisk)	68 ±3	Not stated; tolerance given
Walk-behind	B 50 W Bp (Kärcher)	65 dBA	Not stated
Walk-behind, eco mode	CT51 with Eco Select (IPC)	"down to 62Db"	Not stated
Walk-behind	T500 (Tennant)	about 67 dBA, about 62 in Quiet-Mode	Not stated (dealer comparison)
Walk-behind	CA30 20B (Clarke)	70 dB A	Not stated
Walk-behind	E20 (Minuteman)	"< = 70dBs"	Not stated; no A-weighting given
Ride-on	B 110 R (Kärcher)	59 dB(A)	Not stated
Ride-on	T16 (Tennant)	68 dBA disk, 71 dBA cylindrical	Operator's ear, ISO 11201
Ride-on	SC6500 (Nilfisk)	70 dB(A)	Not stated
Robotic	KIRA B 50 (Kärcher)	69 dB(A)	Not stated
Robotic	T7AMR (Tennant)	"As low as 70 dBA"	Not stated
Sweeper-scrubber, battery	M17 (Tennant)	75 dBA, uncertainty 3 dBA	Operator's ear, IEC 60335-2-72
Sweeper-scrubber, LPG	SC8000 1300 LPG (Nilfisk)	84 dB(A)	1.5 m, ISO 3744
Sweeper-scrubber, diesel	SC8000 1300 Diesel (Nilfisk)	83 dB(A)	1.5 m, ISO 3744

The HFM figures come from a 2014 trade magazine article and the T500 figures from a dealer page. We list them because buyers still quote them.

Class predicts loudness less than you would think. Kärcher's B 110 R ride-on is listed at 59 dB(A), below most walk-behinds, and Kärcher pitches it at "noise-sensitive areas (daytime cleaning, hospitals, hotels, etc.)". Robots are not quiet by default: the KIRA B 50 and T7AMR are listed at 69 and 70, the same as a standard walk-behind (see robotic floor scrubbers).

The engine is what makes a machine loud. The LPG and diesel SC8000 are listed 8 to 9 dB above Tennant's battery M17 sweeper-scrubber. The two were measured at different positions, so the gap is approximate, but no battery machine in the table comes within 8 dB of them.

Quiet modes are worth 5 to 9 dB. Tennant's T300 drops 7.1 dB on the 430 mm disk (64.9 to 57.8 dBA) and 8.8 dB on the orbital head (66.4 to 57.6). Nilfisk's SC401 drops 5 dB. HFM says makers get there "by reducing vacuum and brush speeds as well as adding insulation", so quiet mode also means weaker pickup. Our vacuum motor guide covers pairing it with low solution flow.

Why the figures are not strictly comparable

Position. Tennant measures at the operator's ear and Nilfisk measures the SC8000 at 1.5 m. Most sheets do not say. Hard corridor walls change how fast the level falls with distance, so one position cannot be converted to another.
Tolerance. Nilfisk prints ±3 on the SC401 and Tennant gives a 3 dBA uncertainty on the M17. A 65 and a 68 from different sheets may be the same machine noise.
Weighting. dB(A) is weighted to human hearing. Minuteman's "70dBs" and IPC's "62Db" do not say they are A-weighted.
Mode. "As low as" and "down to" figures describe the quietest setting, not full scrub.

Tennant names ISO 11201, "as recommended by the American Association of Cleaning Equipment manufacturers & OSHA", or IEC 60335-2-72; Nilfisk names ISO 3744 for the SC8000. When noise decides a purchase, ask the dealer for the standard, position and mode behind the figure. Our guide to floor scrubber specs covers the other numbers that need the same question.

Against OSHA 90 dBA and NIOSH 85 dBA

OSHA (29 CFR 1910.95) allows 90 dBA over 8 hours with a 5 dB exchange rate (95 dBA for 4 hours, 100 for 2), and requires a hearing conservation program at an 8-hour average of 85 dBA. NIOSH recommends 85 dBA over 8 hours, and "for each 3 dBA increase in noise level," half the time, so 88 dBA is a 4-hour limit.

Published level	Versus NIOSH 85 dBA (8 h)	Versus OSHA 90 dBA (8 h)
52 to 71 dB(A): micro, walk-behind, riders, robots	14 to 33 dB below	19 to 38 dB below
75 dBA: battery sweeper-scrubber (Tennant M17)	10 dB below	15 dB below
83 to 84 dB(A): LPG or diesel sweeper-scrubber (Nilfisk SC8000)	1 to 2 dB below	6 to 7 dB below

A published sound level is not a worker's exposure. Both limits apply to the average the operator actually receives over a shift, from every source in the building. A battery scrubber alone will not reach either limit. An LPG combination machine run all shift in an already loud plant can, so measure those operators' exposure.

Targets for hospitals, schools and offices

These numbers are far lower, and they describe the room, not the machine.

Space	Guideline (WHO, Community Noise)
Hospital ward rooms, night	30 dB LAeq, with 40 dB LAmax
Rooms where patients are treated, observed or resting	35 dB LAeq
School classrooms during teaching	35 dB LAeq
Normal speaking voice at 1 m, for comparison	about 60 dBA (relaxed 54 to 56, raised 66)

No scrubber meets 30 or 35 dB, so the answer is timing and mode. Our recommendations:

Hospitals. Scrub patient rooms when empty. In inpatient corridors at night use the quietest mode and machines published under 60 dB(A), such as the T300 in Quiet-Mode, the B 110 R or the BR 30/1 C. HFM calls floor cleaning equipment "one of the primary contributors to noise in hospitals". See our healthcare guide.
Schools. Scrub classrooms after dismissal. Corridors during class time only with a sub-60 machine and closed doors (see schools and universities).
Offices. A 65 to 70 dB(A) walk-behind is louder than a normal voice at 1 m, so nearby conversations stop. Use quiet mode in working hours and full power in the evening.

When these numbers stop applying

Every figure is a new machine under test conditions. A worn or blocked vacuum motor gets louder and higher pitched (see loud vacuum motor), and brush chatter or a dry deck adds noise no sheet measured. Tile, glass and atriums reflect sound back. If noise decides the purchase, demo the machines in your own corridor and measure each one with the same meter, at the same spot, in each mode. Two machines measured that way can be compared. Two spec sheets often cannot.

Frequently asked questions

How many decibels is a floor scrubber?