Type NL

With sound reduction characteristics

Acoustic louvres as a protection of air conditioning systems against the direct ingress of rain, leaves and birds into fresh air and exhaust air openings

  • Maximum width of 1800 mm, maximum height of 2250 mm
  • Low differential pressure due to aerofoil blades
  • Low air-regenerated noise
  • All aerodynamic data is measured in aerodynamics and acoustics laboratories
  • Absorption material faced with glass fibre fabric and retained by perforated sheet metal
  • Double bank of louvre blades for demanding acoustic requirements
  • Non-active section, without acoustic function, for a uniform appearance
  • Multi-section constructions for large dimensions


Optional equipment and accessories

  • Powder-coated

Acoustic louvre, variant NL-A 00136524_0


  • Application
  • Description

Application

  • Acoustic louvres of Type NL for the fresh air and exhaust air openings of air conditioning systems
  • Protection against the direct ingress of rain as well as against leaves and birds
  • Recommended face velocity for fresh air openings: 2 – 2.5 m/s max.
  • Weather and noise protection with a compact-depth unit

Special characteristics

  • Two construction depths for normal and demanding acoustic requirements
  • Aerofoil blades
  • Absorption material retained by perforated sheet metal

Nominal sizes

  • B: 300, 450, 600, 750, 900, 1050, 1200, 1350, 1500, 1650, 1800 mm
  • Width subdivided: 1950, 2100, 2250, 2400, 2550, 2700, 2850, 3000, 3150, 3300, 3450, 3600 mm
  • H: 300, 450, 600, 750, 900, 1050, 1200, 1350, 1500, 1650, 1800, 1950, 2100, 2250 mm
  • Height subdivided: 2400, 2550, 2700, 2850, 3000, 3150, 3300, 3450, 3600, 3750, 3900, 4050, 4200, 4350, 4500 mm
  • Any combination of B × H
  • Other dimensions upon request

Variants

  • NL: Acoustic louvre
  • NL-H: Double bank for demanding acoustic requirements
  • NL-D: Non-active section for a uniform appearance

Construction

  • S: Galvanised sheet steel
  • A: Aluminium

Parts and characteristics

  • Casing
  • Sound absorbing blades (NL, NL-D)
  • Bird mesh (NL, NL-D)
  • Blades (NL-D)
  • Rear blanking plate (NL-D)

Construction features

  • Aerofoil blades, 150 mm blade pitch
  • Casing with fixing holes for wall installation
  • Absorption material faced with glass fibre fabric and retained by perforated sheet metal (NL, NL-H)
  • Bird mesh 12 × 12 × 1 mm (NL, NL-H)

Materials and surfaces

  • Casing and blades made of galvanised sheet steel (S) or aluminium (A)
  • Perforated sheet metal to retain absorption material is made of galvanised sheet steel (NL, NL-H)
  • Bird mesh made of galvanised steel (NL, NL-H)
  • Absorption material is mineral wool (NL, NL-H)


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/EG
  • Faced with glass fibre fabric as a protection against erosion through airflow velocities of up to 20 m/s
  • Inert to fungal and bacterial growth

Standards and guidelines

  • Insertion loss and sound power level of air-regenerated noise tested to ISO 7235
  • Sound reduction index determined according to EN ISO 10140-2 und EN ISO 717-1

Maintenance

  • Maintenance-free as construction and materials are not subject to wear

Technical information

Function, Technical data, Quick sizing, Specification text, Order code, Related products

  • Function
  • Technical data
  • Quick sizing
  • Specification text
  • Order code
Schematic illustration of NL 00100015_0
① Casing
② Bird mesh
③ Absorption material
④ Glass fibre fabric
⑤ Perforated sheet metal


Functional description

External weather louvres are externally mounted air transfer devices for the fresh air and exhaust air of air conditioning systems. They are installed in external walls and façades. Their narrowly arranged blades give good protection against the direct ingress of rain as well as against leaves and birds.

Under certain unfavourable conditions, such as heavy rain, and depending on the airflow velocity it might happen that slight quantities of water enter together with the air.

This is why the airflow velocity in fresh air openings should not exceed 2 – 2.5 m/s.

Nominal sizes

300 × 450 to 1800 × 2250 mm

Width subdivided

Up to 3600 mm

Height subdivided

Up to 4500 mm

Volume flow rate range (undivided construction)

185 – 6770 l/s or 666 – 24372 m³/h at 1.75 m/s

Total differential pressure – exhaust air (single louvre)

30 – 100 Pa at 1.75 m/s (depending on height)

Total differential pressure – fresh air (single louvre)

25 – 75 Pa at 1.75 m/s (depending on height)


Insertion loss

Variant Centre frequency fm [Hz]
Variant 63 125 250 500 1000 2000 4000 8000
Variant De
Variant dB

NL

3

4

7

8

13

15

13

15

NL-H

3

6

9

16

21

24

24

30


Sound reduction index

Variant Centre frequency fm [Hz]
Variant 63 125 250 500 1000 2000 4000
Variant R RW
Variant dB

NL

6

6

9

13

14

12

NL-H

7

9

16

25

27

21


Quick sizing tables provide a good overview of the volume flow rates with an airflow velocity of 2.5 m/s. Values for intermediate widths can be interpolated. Precise intermediate values and volume flow rates for other airflow velocities can be calculated with our Easy Product Finder design programme.

The sound power levels LWA apply to external weather louvres with a flow cross section of 1 m².

NL, width 300 – 1050 mm, volume flow rate at max. 2.5 m/s

Height Width [mm]
Height 300 450 600 750 900 1050
mm l/s m³/h l/s m³/h l/s m³/h l/s m³/h l/s m³/h l/s m³/h

450

120

432

180

648

240

864

300

1080

360

1296

420

1512

600

240

864

360

1296

480

1728

600

2160

720

2592

840

3024

750

360

1296

540

1944

720

2592

900

3240

1080

3888

1260

4536

900

480

1728

720

2592

960

3456

1200

4320

1440

5184

1680

6048

1050

600

2160

900

3240

1200

4320

1500

5400

1800

6480

2100

7560

1200

720

2592

1080

3888

1440

5184

1800

6480

2160

7776

2520

9072

1350

840

3024

1260

4536

1680

6048

2100

7560

2520

9072

2940

10584

1500

960

3456

1440

5184

1920

6912

2400

8640

2880

10368

3360

12096

1650

1080

3888

1620

5832

2160

7776

2700

9720

3240

11664

3780

13608

1800

1200

4320

1800

6480

2400

8640

3000

10800

3600

12960

4200

15120

1950

1320

4752

1980

7128

2640

9504

3300

11880

3960

14256

4620

16632

2100

1440

5184

2160

7776

2880

10368

3600

12960

4320

15552

5040

18144

2250

1560

5616

2340

8424

3120

11232

3900

14040

4680

16848

5460

19656


NL, width 1200 – 1800 mm, volume flow rate at max. 2.5 m/s

Height Width [mm]
Height 1200 1350 1500 1650 1800
mm l/s m³/h l/s m³/h l/s m³/h l/s m³/h l/s m³/h

450

480

1728

540

1944

600

2160

660

2376

720

2592

600

960

3456

1080

3888

1200

4320

1320

4752

1440

5184

750

1440

5184

1620

5832

1800

6480

1980

7128

2160

7776

900

1920

6912

2160

7776

2400

8640

2640

9504

2880

10368

1050

2400

8640

2700

9720

3000

10800

3300

11880

3600

12960

1200

2880

10368

3240

11664

3600

12960

3960

14256

4320

15552

1350

3360

12096

3780

13608

4200

15120

4620

16632

5040

18144

1500

3840

13824

4320

15552

4800

17280

5280

19008

5760

20736

1650

4320

15552

4860

17496

5400

19440

5940

21384

6480

23328

1800

4800

17280

5400

19440

6000

21600

6600

23760

7200

25920

1950

5280

19008

5940

21384

6600

23760

7260

26136

7920

28512

2100

5760

20736

6480

23328

7200

25920

7920

28512

8640

31104

2250

6240

22464

7020

25272

7800

28080

8580

30888

9360

33696


NL, differential pressure and sound power level

v vt Installation type
v vt A B C D
v vt Δpt LWA Δpt LWA Δpt LWA Δpt LWA
m/s Pa dB(A) Pa dB(A) Pa dB(A) Pa dB(A)

1.5

0.2 – 0.4

2

<15

2

<15

2

<15

1

<15

2

0.2 – 0.6

4

<15

4

<15

4

<15

4

<15

4

0.4 – 1.2

18

32

14

28

18

29

14

27

6

0.7 – 1.7

40

44

30

40

40

41

28

39

8

0.9 – 2.3

70

52

50

48

65

49

50

47

10

1.1 – 2.9

110

58

80

54

105

55

75

53


NL-H, Differential pressure and sound power level

v vt Installation type
v vt A B C D
v vt Δpt LWA Δpt LWA Δpt LWA Δpt LWA
m/s Pa dB(A) Pa dB(A) Pa dB(A) Pa dB(A)

1

0.1 – 0.3

2

<15

2

<15

2

<15

2

<15

2

0.2 – 0.6

8

26

6

19

6

18

6

18

3

0.3 – 0.9

16

37

12

30

12

29

12

29

4

0.4 – 1.2

26

45

20

38

20

37

20

37

5

0.6 – 1.5

40

52

30

45

30

44

30

44

7

0.8 – 2.0

80

61

65

54

60

53

60

53


Rectangular acoustic louvres as a protection of air conditioning systems against the direct ingress of rain, leaves and birds into fresh air and exhaust air openings.

Ready-to-install component which consists of a border, aerofoil rain defence blades, and a wire mesh at the rear.

Insertion loss measured according to ISO 7235, sound reduction index measured according to EN ISO 10140-2.

Special characteristics

  • Two construction depths for normal and demanding acoustic requirements
  • Aerofoil blades
  • Absorption material retained by perforated sheet metal

Materials and surfaces

  • Casing and blades made of galvanised sheet steel (S) or aluminium (A)
  • Perforated sheet metal to retain absorption material is made of galvanised sheet steel (NL, NL-H)
  • Bird mesh made of galvanised steel (NL, NL-H)
  • Absorption material is mineral wool (NL, NL-H)


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/EG
  • Faced with glass fibre fabric as a protection against erosion through airflow velocities of up to 20 m/s
  • Inert to fungal and bacterial growth

Construction

  • S: Galvanised sheet steel
  • A: Aluminium

Technical data

  • Nominal sizes: 300 × 450 to 1800 × 2250 mm
  • Width subdivided: up to 3600 mm
  • Height subdivided: Up to 4500 mm
  • Volume flow rate range (undivided construction): 185 – 6770 l/s or 666 – 24372 m³/h at 1.75 m/s
  • Total differential pressure – exhaust air (single louvre): 30 – 100 Pa (depending on height) at 1.75 m/s
  • Total differential pressure – fresh air (single louvre): 25 – 75 Pa (depending on height) at 1.75 m/s

Sizing data

  • V _______________________ [m³/h]
  • Δpt _______________________ [Pa]

Air-regenerated noise

  • LWA _______________________ [dB(A)]

Weighted sound reduction index

  • RW _______________________ [dB]

This specification text describes the general properties of the product. Texts for variants can be generated with our Easy Product Finder design programme.

00135479_0

 Type
NL       Acoustic louvre

 Acoustic performance
       No entry: standard requirement, single louvre
H       High, double bank
D       Non-active section

 Material
S       Galvanised steel
A       Raw aluminium

 

 Nominal size [mm]
       B × H

 Surface
       No entry: standard construction
P1       Powder-coated, RAL Classic colour

       Gloss level
       RAL 9010 50 %
       RAL 9006 30 %
       All other RAL colours 70 %

Order example: NL–H–S/1050×750

Acoustic performance

High

Material

Galvanised steel

Nominal size

1050×750 mm

Surface

Standard construction


 

Variants, Dimensions and weight

  • Variants
  • Dimensions and weight

NL

Variant

  • Acoustic louvre

Parts and characteristics

  • Casing
  • Sound absorbing blades
  • Bird mesh

Construction features

  • Aerofoil blades, 150 mm blade pitch
  • Casing with fixing holes for wall installation
  • Absorption material faced with glass fibre fabric and retained by perforated sheet metal
  • Bird mesh 12 × 12 × 1 mm

Materials and surfaces

  • Casing and blades made of galvanised sheet steel (S) or aluminium (A)
  • Perforated sheet metal to retain absorption material is made of galvanised sheet steel
  • Bird mesh made of galvanised steel
  • Absorption material is mineral wool


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/EG
  • Faced with glass fibre fabric as a protection against erosion through airflow velocities of up to 20 m/s
  • Inert to fungal and bacterial growth

NL-H

Variant

  • High performance acoustic louvre (double bank)

Parts and characteristics

  • Casing
  • Sound absorbing blades
  • Bird mesh

Construction features

  • Aerofoil blades, 150 mm blade pitch
  • Casing with fixing holes for wall installation
  • Absorption material faced with glass fibre fabric and retained by perforated sheet metal
  • Bird mesh 12 × 12 × 1 mm

Materials and surfaces

  • Casing and blades made of galvanised sheet steel (S) or aluminium (A)
  • Perforated sheet metal to retain absorption material is made of galvanised sheet steel
  • Bird mesh made of galvanised steel
  • Absorption material is mineral wool


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/EG
  • Faced with glass fibre fabric as a protection against erosion through airflow velocities of up to 20 m/s
  • Inert to fungal and bacterial growth

NL-D

Variant

  • Non-active section for a uniform appearance

Parts and characteristics

  • Casing
  • Blades
  • Rear blanking plate

Construction features

  • Aerofoil blades, 150 mm blade pitch
  • Casing with fixing holes for wall installation

Materials and surfaces

  • Casing and blades made of galvanised sheet steel (S) or aluminium (A)

Materials

Part Order code detail Material Notes

Casing and blades

S

Galvanised sheet steel


Casing and blades

A

Aluminium


Perforated sheet metal to retain absorption material

Galvanised sheet steel

Only NL, NL-H

Bird mesh

Galvanised steel

Only NL, NL-H

Absorption material

Mineral wool

Only NL, NL-H


Surfaces

Part Order code detail Surface Notes

Casing and blades

Untreated


Casing and blades

P1-RAL ...

Powder-coated, RAL colour ... CLASSIC



NL-S, Weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

7

10

13

16

19

23

26

29

32

36

39

600

9

13

17

22

26

30

35

39

43

48

52

750

11

16

22

27

32

38

43

49

54

59

65

900

13

19

26

32

39

45

52

58

65

71

78

1050

15

23

30

38

45

53

61

68

76

83

91

1200

17

26

35

43

52

61

69

78

86

95

104

1350

19

29

39

49

58

68

78

88

97

107

117

1500

22

32

43

54

65

76

86

97

108

119

130

1650

24

36

48

59

71

83

95

107

119

131

143

1800

26

39

52

65

78

91

104

117

130

143

156

1950

28

42

56

70

84

98

112

126

140

154

169

2100

30

45

61

76

91

106

121

136

151

166

181

2250

32

49

65

81

97

113

130

146

162

178

194


NL-A, weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

5

7

10

12

14

17

19

21

24

26

28

600

6

10

13

16

19

22

25

28

32

35

38

750

8

12

16

20

24

28

32

35

39

43

47

900

10

14

19

24

28

33

38

43

47

52

57

1050

11

17

22

28

33

39

44

50

55

61

66

1200

13

19

25

32

38

44

50

57

63

69

76

1350

14

21

28

35

43

50

57

64

71

78

85

1500

16

24

32

39

47

55

63

71

79

87

95

1650

17

26

35

43

52

61

69

78

87

95

104

1800

19

28

38

47

57

66

76

85

95

104

113

1950

21

31

41

51

61

72

82

92

102

113

123

2100

22

33

44

55

66

77

88

99

110

121

132

2250

24

35

47

59

71

83

95

106

118

130

142


NL-H-S, weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

13

19

26

32

39

45

52

58

65

71

78

600

17

26

35

43

52

61

69

78

86

95

104

750

22

32

43

54

65

76

86

97

108

119

130

900

26

39

52

65

78

91

104

117

130

143

156

1050

30

45

61

76

91

106

121

136

151

166

181

1200

35

52

69

86

104

121

138

156

173

190

207

1350

39

58

78

97

117

136

156

175

194

214

233

1500

43

65

86

108

130

151

173

194

216

238

259

1650

48

71

95

119

143

166

190

214

238

261

285

1800

52

78

104

130

156

181

207

233

259

285

311

1950

56

84

112

140

169

197

225

253

281

309

337

2100

61

91

121

151

181

212

242

272

302

333

363

2250

65

97

130

162

194

227

259

292

324

356

389


NL-H-A, weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

10

14

19

24

28

33

38

43

47

52

57

600

13

19

25

32

38

44

50

57

63

69

76

750

16

24

32

39

47

55

63

71

79

87

95

900

19

28

38

47

57

66

76

85

95

104

113

1050

22

33

44

55

66

77

88

99

110

121

132

1200

25

38

50

63

76

88

101

113

126

139

151

1350

28

43

57

71

85

99

113

128

142

156

170

1500

32

47

63

79

95

110

126

142

158

173

189

1650

35

52

69

87

104

121

139

156

173

191

208

1800

38

57

76

95

113

132

151

170

189

208

227

1950

41

61

82

102

123

143

164

184

205

225

246

2100

44

66

88

110

132

154

176

199

221

243

265

2250

47

71

95

118

142

165

189

213

236

260

284


NL-D-S, weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

3

5

7

8

10

11

13

15

16

18

19

600

4

7

9

11

13

15

17

19

22

24

26

750

5

8

11

14

16

19

22

24

27

30

32

900

7

10

13

16

19

23

26

29

32

36

39

1050

8

11

15

19

23

27

30

34

38

42

45

1200

9

13

17

22

26

30

35

39

43

48

52

1350

10

15

19

24

29

34

39

44

49

54

58

1500

11

16

22

27

32

38

43

49

54

59

65

1650

12

18

24

30

36

42

48

54

59

65

71

1800

13

19

26

32

39

45

52

58

65

71

78

1950

14

21

28

35

42

49

56

63

70

77

84

2100

15

23

30

38

45

53

61

68

76

83

91

2250

16

24

32

41

49

57

65

73

81

89

97


NL-D-A, weight

H B [mm]
H 300 450 600 750 900 1050 1200 1350 1500 1650 1800
mm kg

450

2

4

5

6

7

8

10

11

12

13

14

600

3

5

6

8

10

11

13

14

16

17

19

750

4

6

8

10

12

14

16

18

20

22

24

900

5

7

10

12

14

17

19

21

24

26

28

1050

6

8

11

14

17

19

22

25

28

30

33

1200

6

10

13

16

19

22

25

28

32

35

38

1350

7

11

14

18

21

25

28

32

35

39

43

1500

8

12

16

20

24

28

32

35

39

43

47

1650

9

13

17

22

26

30

35

39

43

48

52

1800

10

14

19

24

28

33

38

43

47

52

57

1950

10

15

21

26

31

36

41

46

51

56

61

2100

11

17

22

28

33

39

44

50

55

61

66

2250

12

18

24

30

35

41

47

53

59

65

71


Installation details, Basic information and nomenclature

  • Installation details
  • Basic information and nomenclature

Installation and commissioning

  • Installation either without installation subframe or with timber subframe, fixing angles, or steel frame made of angle sections (to be provided by others)
  • Install subdivided constructions either horizontally next to each other or vertically on top of each other
  • Seal perimeter gap with mastic
  • Fix cover strips

Installation information

  • Casing with slotted holes of 10 × 15 mm along the side panels

Nomenclature

LWA [dB(A)]

A-weighted sound power level of air-regenerated noise for the louvre

A [m²]

Upstream cross section

v [m/s]

Airflow velocity based on the upstream cross section

vt [m/s]

Airflow velocity based on the upstream cross section (type NL)

V [m³/h] and [l/s]

Volume flow rate

Δpt [Pa]

Total differential pressure


All sound power levels are based on 1 pW.

De [dB]

Insertion loss

Measured with sound transmission from inside to outside

R [dB]

Sound reduction index

RW [dB]

Weighted sound reduction index

Measured with sound transmission from inside to outside

Principal dimensions

B [mm]

Duct width

B₁ [mm]

Duct width for subdivided louvres

H [mm]

Duct height

H₁ [mm]

Duct height for subdivided louvres

n [ ]

Number of flange screw holes

m [kg]

Weight

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