The stated differential pressures for circular silencers correspond to the values for smooth pipes. Deviations, if any, are of no practical relevance.

For ductwork calculation, if the length of a circular silencer is included in the total length of the ductwork, no extra length must be added.

Sizing example

Given data

Circular duct nominal size 160

V = 195 l/s (702 m³/h)

D_e = 5 dB at 250 Hz

Quick sizing

CS025, length 1500 mm

CS050, lenght 500 mm

Selected

CS050, length 500 mm

Δp_st = 4 Pa

CS025 (insulation thickness 25 mm), insertion loss

Nominal size	Nominal length	Centre frequency fm [Hz]
Nominal size	Nominal length	63	125	250	500	1000	2000	4000	8000
Nominal size	Nominal length	De
Nominal size	mm	Hz
80	500	1	2	4	9	20	16	15	10
80	1000	3	5	10	21	44	46	37	23
80	1500	3	5	13	28	47	48	44	31
100	500	1	1	4	8	17	14	12	9
100	1000	2	3	8	17	44	34	28	21
100	1500	2	4	12	24	47	41	34	26
125	500	1	1	3	8	15	11	9	7
125	1000	2	3	7	17	43	30	24	17
125	1500	2	3	10	22	45	34	28	20
160	500	1	1	2	5	14	10	8	6
160	1000	1	1	4	12	40	27	20	16
160	1500	2	2	6	16	42	30	25	19
200	500	1	1	2	5	14	9	6	5
200	1000	1	1	3	11	35	22	16	13
200	1500	2	2	5	15	41	27	19	15
250	500	0	1	2	5	13	8	5	4
250	1000	1	1	3	11	30	19	12	10
250	1500	1	2	5	15	38	25	14	11
315	500	0	1	1	4	9	7	4	3
315	1000	0	1	3	9	21	10	12	8
315	1500	1	2	4	12	27	19	13	10
400	500	0	0	1	3	6	5	3	3
400	1000	0	1	3	8	16	8	8	7
400	1500	1	1	4	10	23	17	11	8

CS050 (insulation thickness 50 mm), insertion loss

Nominal size	Nominal length	Centre frequency fm [Hz]
Nominal size	Nominal length	63	125	250	500	1000	2000	4000	8000
Nominal size	Nominal length	De
Nominal size	mm	Hz
80	500	4	5	11	20	30	27	16	12
80	1000	8	14	23	47	50	50	44	27
80	1500	11	14	33	48	50	50	47	37
100	500	3	4	9	17	24	21	12	10
100	1000	7	10	21	38	50	50	29	22
100	1500	10	11	27	44	50	50	37	30
125	500	2	3	7	14	20	16	11	9
125	1000	5	7	16	32	50	42	25	22
125	1500	7	9	21	41	50	46	33	27
160	500	2	2	6	12	17	14	8	6
160	1000	4	5	12	26	47	34	20	16
160	1500	5	7	17	37	48	42	24	19
200	500	1	2	5	12	16	11	6	5
200	1000	3	5	11	25	45	26	16	13
200	1500	4	6	14	37	48	34	18	15
250	500	1	2	4	12	15	8	5	4
250	1000	2	4	9	25	40	19	12	10
250	1500	3	5	11	35	45	25	14	11
315	500	1	1	3	9	12	6	4	3
315	1000	1	4	8	22	28	13	12	8
315	1500	2	4	10	26	35	19	12	10
400	500	1	1	3	7	9	6	4	3
400	1000	1	4	8	18	23	11	10	7
400	1500	2	4	9	20	26	17	11	8

CS, differential pressure

Nominal size	V		Nennlänge [mm]
Nominal size	V		500	1000	1500
Nominal size	V		∆pst
Nominal size	l/s	m³/h	Pa
80	20	72	2	4	6
80	40	144	6	12	16
80	50	180	8	16	25
80	55	198	12	25	35
100	30	108	2	2	4
100	60	216	4	8	12
100	75	270	6	12	18
100	90	324	8	18	25
125	50	180	2	2	4
125	95	342	4	6	10
125	120	432	6	10	14
125	145	522	6	14	20
160	80	288	2	2	2
160	155	558	2	6	8
160	195	702	4	8	10
160	235	846	6	10	14
200	125	450	2	2	2
200	245	882	2	4	6
200	310	1116	4	6	8
200	370	1332	4	8	10
250	195	702	<2	<2	<2
250	385	1386	<2	4	4
250	485	1746	2	4	6
250	580	2088	4	6	8
315	310	1116	<2	<2	<2
315	615	2214	<2	2	4
315	770	2772	<2	4	4
315	925	3330	2	4	6
400	500	1800	<2	<2	<2
400	995	3582	<2	<2	2
400	1245	4482	<2	2	4
400	1495	5382	<2	4	4

Circular silencers for air conditioning systems, rigid construction, available in 8 nominal sizes.

Insertion loss measured according to ISO 7235.

Casing with acoustic and thermal insulation.

Spigot with groove for lip seal, suitable for circular connecting ducts to EN 1506 or EN 13180.

Casing air leakage to EN 15727, class D.

Special features

• Insertion loss measured according to ISO 7235
• Absorption material is non-combustible
• Insulation thickness 25 mm or 50 mm

Materials and surfaces

• Casing and perforated inner duct made of aluminium
• Lining is mineral wool
• End pieces made ABS plastic, flammability to UL  94, V-0 (nominal sizes 80 – 125)
• End pieces made of aluminium (nominal sizes 160 – 400)

Mineral wool

• To EN 13501, fire rating class A1, non-combustible
• RAL quality mark RAL-GZ 388
• Biosoluble and hence hygienically safe according to the German TRGS 905 (Technical Rules for Hazardous Substances) and EU directive 97/69/EC
• Inert to fungal and bacterial growth

Technical data

• Nominal sizes: 80 to 400 mm
• Operating pressure: 1000 Pa max.
• Operating temperature: 100 °C max.

Sizing data

• D _______________________ [mm]
• H _______________________ [mm]
• Insulation thickness __________ [mm]
• V _______________________ [m³/h]
• D_e at 250 Hz ________________ [dB]
• Δp_st _______________________ [Pa]

CS

Variant

• Circular silencer for the reduction of noise
• Spigot

CS/.../AS2

Variant

• Circular silencer for the reduction of noise
• Socket-type spigots to make connections to the ducting

CS/.../BK2

Variant

• Circular silencer for the reduction of noise
• With raised edges to make detachable connections to the ducting

Installation and commissioning

• Any installation orientation
• Installation in ducts outside of closed rooms requires sufficient protection against the effects of weather

Principal dimensions

ØD [mm]

Outer diameter of the spigot

ØD₃ [mm]

Outer diameter of circular silencers

L [mm]

Length of attenuator/silencer including spigot (in airflow direction)

L₁ [mm]

Length of acoustic cladding and acoustically effective length

B [mm]

Attenuator width and duct width (upright splitters)

H [mm]

Attenuator height and duct height (upright splitters)

T [mm]

Splitter thickness

S [mm]

Airway width

n [ ]

Number of flange screw holes

m [kg]

Weight

Nomenclature

f_m [Hz]

Octave band centre frequency

L_WA [dB(A)]

A-weighted sound power level of air-regenerated noise

D_e [dB]

Insertion loss

V [m³/h] and [l/s]

Volume flow rate

Δp_st [Pa]

Static differential pressure

All sound power levels are based on 1 pW.

All values were measured in a TROX lab and to EN ISO 7235. Intermediate values may be achieved by interpolation.

Lab measurements exceeding 50 dB are indicated as 50 dB, in line with common practice.