“110 dB” isn’t a coverage guarantee

The number on the spec sheet (e.g., 110 dB @ 1 m) is not the volume your operators hear at 8, 12, or 20 metres,  and it says nothing about echoes, masking noise, or the fact that many workers wear hearing protection. This guide shows how to translate that headline figure into reliable, even coverage, with spacing rules, mounting tips, and a quick commissioning process any maintenance team can run.

The combined device that solves both sound and sight: Flameproof Hooter with Flasher 110 dB.

Understand decay & masking in 3 minutes

1. Distance loss: In open areas, a simple rule is ~6 dB loss per distance doubling.
   
   
2. Ambient masking: If your hall runs at 90 dB, your alarm must be roughly +10–15 dB above that at the listener’s ear to be clearly recognized.
   
   
3. Reverberation: Long, reflective spaces blur tones; “louder” isn’t always “clearer.” Multiple moderate sources pointed out that people work better than one blasting horn.
   
   

A quick spacing method (worked example)

Ambient: 90 dB. Target: 102 dB at listener positions.
One 110 dB unit at 12 m:

• 1→2 m: 104 dB
  
  
• 2→4 m: 98 dB
  
  
• 4→8 m: 92 dB
  
  
• 8→16 m: 86 dB

At ~12 m, you’re around 89–92 dB, below target.
Fix: Put people within 6–10 m of a device indoors (shorter in very noisy zones). Add units rather than trying to push a single device further.

Mounting height & angle

1. Height: 2.5–4 m keeps the device above traffic but still projecting at ear level.
   
   
2. Angle: Slight downward tilt toward the listener plane; avoid aiming at reflective sheet metal or stairwells.
   
   
3. Sightlines: The flasher lens must be seen from key work positions; avoid pipework shadows.
   
   

Use the flasher to compensate for PPE and echoes

The visual strobe ensures the alarm is perceived even when the tone is partially masked by earmuffs or echo. In night shifts, you can shorten the audible duration but keep a more persistent visual pulse.

Commissioning: 20-minute walk test

1. Trigger the alarm during peak noise.
   
   
2. Walk standard routes with operators wearing their usual PPE.
   
   
3. Mark dead spots for audio or visual; add units or re-aim as needed.
   
   
4. Log tap settings, device IDs, and final angles on a simple map.
   
   

Need a baseline audible withouta  beacon? Flameproof Hooter.

Maintenance plan

1. Monthly: Quick function test; lens/grille clean.
   
   
2. Quarterly: Re-torque hardware; check that levels still beat ambient.
   
   
3. Post-change: Any new machinery or rack? Re-check coverage.
   
   

Mistakes to avoid

1. Sizing from the catalogue SPL alone.
   
   
2. A single horn for a huge bay.
   
   
3. Mounting behind signage or ductwork.
   
   
4. Commissioning after hours instead of during real production.
   
   

FAQs

Q1. What if ambient varies by shift?
Set zones with independent levels; verify on each shift’s peak noise.

Q2. How many devices for a 30×40 m bay?
Often 3–6, depending on obstructions and ambient. Start with a walk test.

Q3. Do I need different colors for different alarms?
Yes, one color per event type across the site improves recognition.

Send us your bay dimensions and a quick video/audio clip during peak noise. We’ll recommend counts, mounting heights, and a spacing plan. Explore devices: Flameproof Hooter with Flasher 110 dB and Flameproof Hooter.