This is something that I've been working on for the past few days. I don't think there's a list like this anywhere (At least, I haven't found one.).
Here's what I have so far, from loudest to quietest. The decibel rating is shown in bold.
138:
Chrysler-Bell Victory Siren
137:
Bell Telephone "Big Bertha"
135:
ACA Penetrator-50
133:
ASC Tempest-135 AC/DC
132
Whelen WPS 4008
130:
ACA Allertor 130
ACA Hurricane 130/MKII
ACA PN-20
ASC RM-130
Federal Signal 2001-130
Sentry 40V2T
129:
ASC Tempest-128
Sentry 16V1T-B AC/DC
Whelen Vortex R4
Whelen WPS-2910
Whelen WPS-4004
128:
ASC EC-12
ASC IForce-3200
CTI SMR15
Federal Signal 2001-SRN
Federal Signal 508
Sentry 20V2T (Square-horned)
Whelen WPS-2909
127:
ACA Penetrator-15
ASC RM-127
Federal Signal Thunderbolt 1000
Hormann HA-416R
Hormann HA-832
Sentry Defender
Werden P-127
Whelen Vortex R3
Whelen WPS-2908
Whelen WPS-4003
126:
ACA Allertor 125
ASC AL-8000
ASC EC-8
ATI HPSS32
Federal Signal Equinox
Federal Signal Thunderbolt 1000T
Federal Signal Thunderbolt 1003
Whelen WPS-2810
Whelen WPS-2907
125:
ACA Alertronic 5000
ACA Penetrator-10
ACA/ASC Cyclone
B&N Mobil Directo (Electric)
Chrysler-Bell Gas Siren
Federal Signal Modulator MOD6048
HOR Super Sirex
Sentry 16V1T-B
Sentry 20V2T
Soundmaster 125
Whelen WPS-2809
Whelen WPS-2906
124:
Federal Signal EOWS 612
Federal Signal Thunderbeam RSH-10
Whelen Vortex R2
Whelen WPS-2808
Whelen WPS-3000
123:
ASC IForce-2800 International
Federal Signal Modulator MOD6032
Hormann ECN 3000
Whelen WPS-2807
Whelen WPS-2905
122:
Sentry 15V2T
121:
ASC AL-6000
ASC EC-1/2/3/4
ASC IForce-2400
ASC/Hormann Tempest-121
ATI HPSS16
Federal Signal DSA6'
Federal Signal Modulator MOD6024
Hormann ECN 2400
Horman HA-416/D
Sentry 7V8-B AC/DC
Whelen WPS-2806
Whelen WPS-2904
120:
ACA Cyclone 120
ASC OM-120
Federal Signal Modulator MOD5020
Federal Signal 500(T)
Sentry 10V2T
Sterling Model M
119:
Federal Signal DSA5'
Whelen WPS-2805
Whelen WPS-2903
118:
ASC IForce-1600
Federal Signal Modulator MOD4016
Hormann ECN 1800
Sentry 7V8-B
Whelen Hornet
Whelen Omnialert OA4
Whelen WPS-2750
Whelen WPS-2804
117:
Federal Signal DSA4'
115:
ACA Banshee 115
ASC AL-4000
CTI SMO15
Federal Signal DSA3'
Federal Signal Eclipse 8
Federal Signal EOWS 115
Federal Signal EOWS 1212
Federal Signal Modulator MOD3012
Federal Signal STH-10
Hormann ECN 1200
Klaxon GP12
Sentry 10V
Soundmaster 115
Whelen Omnialert OA3
Whelen WPS-2740
Whelen WPS-2803
Whelen WPS-2902
114:
Federal Signal STL-10
Whelen Omnialert OA2
Whelen WPS-2802
113:
ASC IForce-800
ASC Tempest-112
Federal Signal Model 5
Federal Signal 2/3T22
112:
ASC AL-2000
Federal Signal Modulator MOD2008
Hormann ECN 900
Sentry 5V
Sentry 7V8
Whelen WPS-2730
111:
Federal Signal DSA2'
110:
ACA Banshee 110
109:
Federal Signal SD-10
Hormann ECN 600
Klaxon GP8
Sentry 3V8-H
Whelen WPS-2901
108:
ACA Screamer 108
ASC AL-1000
Federal Signal Model 5T
Whelen Omnialert OA1
Whelen WPS-2801
107:
Federal Signal Eclipse NH
Sentry 3V8
106:
Federal Signal Modulator MOD1004
105:
ACA Screamer 105
CLM Omni-Directional
Federal Signal Model 3
Klaxon GP6
Klaxon/Secomak S30
103
Hormann ECN 300
Hormann E57
102:
Federal Signal Model 2
100:
ACA Screamer 100
Federal Signal Model 2T
Secomak/Grifco 999
95:
ACA Sentry 95
94:
Klaxon/Secomak GP3
Secomak/Grifco 888
Most of these were obtained from the company websites (Though for some reason I cannot access the Whelen company page, that's why I don't have any on this list.), or from other various places online. However, it's far from complete, so I'll need YOUR help to finish it. If you guys would be so kind as to give me the decibel ratings of any siren that you know of that isn't on this list, I will add them.
Much appreciated!