zvezek 1 - ANG.indd - Hidria

SLOT DIFFUSERS, ROUND DUCT DIFFUSERS 

Slot diffusers LD-13, LD-14, LD-15 

LD-13 

LD-14 

LD-15 

SLOT DIFFUSERS 

Application: 

Slot diffusers are designed for air supply in rooms 

with floor to ceiling heights of 2.5 to 4 m. They 

are suitable for supplying either cold or warm air, 

in particular in applications where air conditioning 

comfort demands are stringent. Due to their high 

induction rate and rapid decrease of temperature 

difference, these diffusers are also suitable for 

variable systems. 

Description: 

Diffuser face plate is made of anodized aluminium 

sections with built-in cylindrical deflectors made 

of recycled plastics. Deflectors allow continuos 

adjustment of discharged air direction within the 

360 o range. The diffuser plenum box is made of 

galvanised sheet steel and has a flow rate control 

damper built in its inlet spigot, to allow fine 

adjustment of the desired air flow rate. 

LD-16N 

Panel design slot diffusers LDP-13 and LDP-14 

LDP-14 

Round duct diffusers SKD-13 

SKD-13D 

Software: Klima ADE 5.3 

LD and SKD Software 

PANEL DESIGN SLOT DIFFUSERS 

A panel design slot diffuser consists of a face 

plate and a plenum box. Cylindrical air deflectors, 

equal to those in LD-13 and LD-14 diffusers, 

are installed in the slots, to allow continuous 

adjustment of discharged air direction within the 

360 o range. On order, diverse plate designs and 

slot patterns are available. 

ROUND DUCT DIFFUSERS 

Application: 

Round duct diffusers can be installed at various 

locations within the duct network. They are suitable 

for supplying either cold or warm air. 

Description: 

They are made of galvanised tubes with slots 

equipped with cylindrical air deflectors equal 

to those in the LD-13 slot diffuser, to allow 

adjustment of air direction and flow rate. As 

standard, the tube and cylindrical deflectors are 

in RAL 9010 white colour. 

SOFTWARE: KLIMA ADE 5.3 

LD and SKD Software: 

- available calculation and graphical display of air 

supply for slot diffusers LD-13, LD-14 and LD-15 

- available calculation of technical specifications 

for the application of wall- or ceiling-mounted 

slot diffusers 

- available calculation of ceiling-mounted 

multiple-diffuser configuration air supply 

- application of vertical or horizontal slot diffuser 

air supply into the room, depending on the 

mode of operation - heating or cooling 

- the package supports basic air supply mode 

models for the SKD-13 round duct diffuser 

- available calculation of SKD-13 round duct 

diffusers 

cooling mode: single-side and two-side 

horizontal supply and alternating horizontal supply 

heating mode: vertical air supply

AIR DISTRIBUTION 

Slot diffusers, Round duct diffusers 

Slot diffusers 

Page 

Slot diffusers LD-13 and LD-14 ............................................................................................................................................................................................162 

Technical data for Slot diffusers LD-13 and LD-14 ...........................................................................................................................................................168 

Slot diffusers LD-15 ..............................................................................................................................................................................................................175 

Floor slot diffusers LD-16N...................................................................................................................................................................................................179 

Panel design slot diffusers LDP-13, LDP-14.........................................................................................................................................................................181 

Round duct diffusers 

Round duct diffusers SKD-13................................................................................................................................................................................................183 

Legend of symbols 

St 

RAL 

9010 

Element is made of aluminium profiles, aluminium sheet or aluminium casting. 

Element is made of steel sheet. 

Element is powder painted in standard RAL 9010 colour. Other desired colour is to be specified in the order. 

Shady symbol means possibility of optional material, surface protection, motor version, ... 

Element is intended to be built in the floor. 

Element is intended to be built in the wall. 

Element is intended to be built in the ceiling or in the wall. 

Element for air conditioning of rooms with floor to ceiling heights room up to 4m. 

Element for air conditioning of rooms with floor to ceiling heights from 6 to 15m. 

Element is suitable for the supply of warm air (heating). 

M 

CD 

Element is suitable for the supply of cool air (cooling). 

Element allows regulation by electric motor (Belimo electric motors). 

Element is intended for air filtration. The filter of class ... is built in. 

The possibility of the automatic selection and calculation of the technical characteristics of grilles and difusers in regard to the given 

conditions with the assistance of the Klima ADE program.

SLOT DIFFUSERS LD-13, LD-14 

LD-13 

LD-14 

RAL 

CD 

Slot diffusers LD-13, LD-14 

Application: 

LD-13 and LD-14 slot diffusers are designed for 

the supply of air in rooms with floor to ceiling 

heights of 2.5 to 4 m for supplying either cold or 

warm air, in particular in applications where air 

conditioning comfort demands are stringent. Due 

to their high induction rate and rapid decrease 

of temperature difference, these diffusers are also 

suitable for variable systems. 

Description: 

LD-13 and LD-14 slot diffusers are designed in 1, 

2, 3 and 4-slot versions. Diffuser face plate 

consists of anodised aluminium sections with 

built-in cylindrical deflectors made of recycled 

plastics. Deflectors allow continuos adjustment 

of discharged air direction within the 360 o range 

as well as control of supply air flow rate. The 

cylindrical deflectors also allow full shutting of 

the diffuser. The slot diffuser plenum box is made 

of galvanised sheet steel and has a flow rate 

control damper built in its inlet spigot, to allow 

fine adjustment of the desired air flow rate. 

B 60 

1 

2 

3 

φ D 

H 

H1 

41 

8.5 

LD-13 

9.4 

5 

6 

Component parts: 

1 Plenum box 

2 Inlet spigot 

3 Volume control damper 

4 Main section 

5 Cylindrical deflector 

6 Side lateral section 

7 Connecting section 

8 Outside insulation 

15 

A 

E 

7 

a 

Installation openings: 

(A+5) x (L+15) 

Control schematic of the spigot volume 

control damper: 

8 

LD-14 

9.4 4 

53 

8.5 

5 

6 

26 

A 7 

E 

Installation openings: 

(A+5) x (L+15) 

162


LD-13/1 

LD-14/1 

LD-13/2 LD-13/3 LD-13/4 

LD-14/2 LD-14/3 LD-14/4 

Slot diffuser types: 

• Single-slot (designation LD-13,14/1) 

• Two slots (designation LD-13,14/2) 

• Three-slots (designation LD-13,14/3) 

• Four-slots (designation LD-13,14/4) 

LD-13 O/1 

LD-13 O/2 

LD-13 O/3 

41.5 

41.5 

41.5 

37.5 

72.5 

LD-14 O/1 

LD-14 O/2 

LD-14 O/3 

53.5 53.5 

53.5 

50 

96.5 

Slot diffusers LD-13 O and LD-14 O 

Narrow version - New installation method 

The narrow slot diffuser differs from the 

conventional slot diffuser construction as 

regards its mounting to the ceiling or wall. 

The conventional slot diffuser has a L-crosssection 

mounting sleeve which remains 

visible and may, in certain applications, interfere 

with aesthetic requirements. The new design has 

eliminated this deficiency as well as introduced 

improved structural rigidity due to its reinforced 

sleeve. The product is thus suitable for 

installation in cooling suspended ceilings as well. 

107 

142 

LD-13 O/4 

41.5 

LD-14 O/4 

53.5 

142 

187.5 

LD-13 O, LD-14 O 

LD-13, LD-14 

LD-13 

No. of slots H H1 B A E F 

1 220 261 95 33 57.5 24.4 

2 230 271 129 67 92 58.2 

3 250 291 162 101 126.5 92.0 

4 290 331 196 135 161.5 125.8 

LD-14 

No. of slots H H1 B A E F 

1 233.5 287 106 44 69 35.3 

2 253.5 307 150 89 115 80 

3 293.5 347 195 133 161.5 124.7 

4 318.5 372 240 178 206.5 169.4 

Standard lenghts L 

LD-13 and LD-14 slot diffusers are available 

in standard lengths ranging from L=300 to 

L=2000 mm, with a 100 mm step. In cases where 

longer diffusers are required, they can be joint 

together by means of (rail-type) connecting plates. 

Plenum boxes are also available in standard 

lengths ranging from 300 mm to 2000 mm. 

Special orders: 

On customer’s request slot diffusers can be made 

in other dimensions. End seals and longitudinal 

sections are painted in any RAL scale colour 

according to the customer’s request. As standard, 

cylindrical deflectors are black or white, on the 

customer’s request, they can be coloured in any 

RAL scale colour. Non-standard colours and extra 

components are to be ordered separately. 

163


L 300 to 1000 1100 to 1500 1600 to 2000 

Number 

Number and diameter of inlet spigots 

of slots LD-13 LD-14 LD-13 LD-14 LD-13 LD-14 

1 1 x 98 1 x 123 2 x 98 2 x 123 2 x 123 2 x 138 

2 1 x 138 1 x 158 2 x 123 2 x 138 2 x 138 2 x 158 

3 1 x 158 1 x 198 2 x 138 2 x 158 2 x 158 2 x 198 

4 1 x 198 1 x 223 2 x 158 2 x 198 2 x 198 2 x 223 

Number and diameter of inlet spigots 

Standard lenghts: from 300 mm to 1000 mm 

Number of slots: 1 

Standard lenghts: from 1000 mm to 2000 mm 


J 

L/2 

L/2 

J 

Position of inlet spigots: 

Number Standard Position 

of inlet spigots length of spigots 

1 300 - 1000 L/2 

2 1100 - 1500 J = 300 

2 1600 - 2000 J = 400 

angle 90˚ 

300 

Slot diffuser face plate designs: 

Slot diffuser face plates are made of linear or 

angular ended sections, which allow the diffusers 

to be joined at different angles Angular ended 

sections are not fitted with air direction controls. 

300 

Cylindrical deflectors: 

Cylindrical deflectors are the most important 

components of a slot diffuser. They allow 

adjustment of both air flow rate and direction. 

Cylindrical deflectors are made of recycled 

plastics. As standard, they are black or white. 

End seals 

End seals are components of the diffuser face plate. 

They are available in two designs: 

• as an angle piece (E – on both ends, ET – on 

one end only) or 

• plates (F – on both ends, FT – on one end 

only). 

The connecting strip-section has no end angle 

pieces or plates seals (designation T). 

Joining diffusers together in length 

and width 

Joining in width (into diffusers with multiple 

slots) requires special strip sections, while joining 

in length requires connecting plates (the total 

length of combined diffusers is not limited). 

164


Fixing of the plenum box onto LD-13, 

LD-14 diffusers 

• with self-tapping screws (designation U) 

• with spring clamps (designation S) 

• with a cross-member (designation Z) 

Fixing with self-tapping 

screws (U) 

Fixing with spring 

clamps (S) 

Fixing with 

a cross-member (Z) 

Installation methods: 

• with a threaded bar (designation R) 

• with a wire (designation R) 

• with suspension brackets on the plenum box 

(designation P) 

• with special fixing elements (designation R) 

• with springs (designation N) 

Installation with 

a threaded bar (R) 

Installation with wire (R) 

Installation with 

suspension bracket (P) 

Installation with special 

fastening elements (R) 

Installation with springs 

into ducts (N) 

165


Types of air discharge 

a 

b 

LD-13 

Discharge direction 

Min. air flow rate 

Max. air flow rate 

Standard 

(left, right) 

Standard 

(right) 

c 

d 

101ß 

Discharge angle 

LD-14 

Standard 

(left) 

Standard 

(vertical) 

Discharge direction 

Min. air flow rate 

Max. air flow rate 

e 

f 

g 

Air jet angle 60 o 

(left, right) 


(right) 


(left) 

Discharge angle 

Top view 

Slot diffuser with actuator controlled 

discharge direction 

Slot diffusers with actuator controlled discharge 

direction are suitable for summer-winter air 

supply applications. The desired direction of air 

jet is achieved by means of an electric actuator 

which moves a slider. Manual adjustment is 

therefore not necessary. Compared with standard 

slot diffusers, air flow rate is reduced by 50 %. 

Component Parts: 

1 Slot diffuser 

2 Deflector 

3 Electric actuator 

In case the discharge angle is to be adjustable 

by means of an electric actuator (winter-summer 

application), this requirement shall be specified 

in the ordering form. 

Every second row 

1 Adjustment of deflectors for warm air supply 

Every second row 

2 Adjustment of deflectors for cold air supply 

166


Ordering key: 

LD-13/1/B/E/K/M/S/P/I/g L=1700 

I5 

I9 

I19 

N 

P 

R 

Z 

S 

U 

Length L=300, 400, 500, ..., 2000 (single piece) 

Type of air discharge (a, b, c, d, e, f, g) 

Thermal insulation (polyethylene), 5 mm thick, on the outside of the plenum box. 

sound and thermal insulation (from -40 o C to 105 o C), 9 mm thick, on the outside of the plenum box 

(synthetic rubber based material). 



Installation with spring clamps – without plenum box (LD-13 and LD-14 only) 

Installation of the plenum box with hangers 

Installation with brackets built in the basic section 

Fixing of the diffuser to the plenum box with a cross-member 

Fixing of the diffuser to the plenum box with spring clamps 

Fixing of the diffuser to the plenum box with self-tapping screws 

M 

K 

Volume control damper 

Plenum box 

E 

ET 

F 

FT 

T 

B 

W 

End sealing on both ends 

End sealing on one end 

End plate on both end 

End plate on one end 

Rail-type without end sealings and plates 

Black deflectors 

White deflectors 

1 

2 

3 

4 

LD-13 

LD-14 

LD-13 O 

LD-14 O 

Number of slots 

Slot diffuser 

Narrow slot diffuser 

• Please specify the deflector colour in your order. 

• Standard eloxal colour of the aluminium section is the original aluminium colour. Other colours shall 

be specified in the order. 

• For the LD-13 0 and LD-14 0 type, the following end seals are available: F, FT and T. 

• When installing in cooling ceilings, consult the manufacturer. 

• In the case the slot diffuser is ordered complete with plenum box, the air jet configuration is set 

as shown on the diagram on page 166. 

• Versions with insulation on the inside of the plenum box are also available. 

167

SLOT DIFFUSERS LD-13, LD-14 TECHNICAL DATA 

Fast selection diagram: L WA < 35 dB(A) 

4 

3 

Nr. of slots 

2 

1 

LD-13 

LD-14 

100 300 500 1000 1200 

Q(m 3 /hm) 

Technical specifications for one-slot 

diffuser, per meter of lenght, 

at horizontal discharge: 

A(m 2 ) Q(m 3 /h) L WA (dB) 

LD-13 0,0092 135 34 

LD-14 0,0136 210 28 

H1 

A 

L 

VH1 

ΔtH 

L 

x 

VL 

ΔtL 

L 

x 

VL 

ΔtL 

H1 

VH1 

ΔtH 

A 

L 

VL 

x 

ΔtL 

Q (m 3 /h) 

x (m) 

H (m) 

L (m) 

V L (m/s) 

Δt z (K) 

Δt L (K) 

Δp (Pa) 

L WA (db(A)) 

v H1 (m/s) 

A, B (m) 

H1 (m) 

Air flow rate 

Horizontal distance to the wall 

Room height 

Throw distance (L=H1+x) 

Air velocity at the throw 

distance L 

Temperate difference between 

the supply and room air 

Difference between the core and 

room air temperature 

Pressure drop 

Sound power level 

Air velocity at the distance H1 

Distance between diffusers, in 

length and in width 

throw distance 

168


Air velocity diagrams for LD-13, at different throw distances: 

One or two sided horizontal discharge: 

H1 (m) 

1 1.2 1.6 2 

LD-13 / 1 160 125 110 90 70 55 45 

LD-13 / 2 230 180 155 125 100 

LD-13 / 3 280 220 185 155 

LD-13 / 4 325 250 215 180 

2.5 

LD-13 / 1 160 125 110 90 70 55 45 

LD-13 / 2 230 180 155 125 100 

LD-13 / 3 280 220 185 155 

LD-13 / 4 325 250 215 180 

0.8 

V H1 (m/s) 

0.4 

0.3 

0.25 

0.2 

V (m/s) 

L 

0.6 

0.5 

0.4 

0.3 

0.25 

0.2 

0.15 

2 2.5 3 4 5 7 10 

A (m) 

0.15 

0.1 

2 2.5 3 4 5 7 10 

L (m) 

Alternate sided horizontal discharge: 

H1 (m) 

1 1.2 1.6 2 

LD-13 / 1 160 125 110 90 70 55 45 

LD-13 / 2 230 180 155 125 100 

LD-13 / 3 340 280 220 185 155 

LD-13 / 4 395 325 250 215 180 

2.5 

LD-13 / 1 160 125 110 90 70 55 45 

LD-13 / 2 230 180 155 125 100 

LD-13 / 3 340 280 220 185 155 

LD-13 / 4 395 325 250 215 180 

0.7 

V H1 (m/s) 

0.3 

0.25 

0.2 

0.15 

0.1 

V (m/s) 

L 

0.5 

0.4 

0.3 

0.25 

0.2 

0.15 

0.1 

2 2.5 3 4 5 7 10 

A (m) 

0.05 

2 2.5 3 4 5 7 10 

L (m) 

169


Air velocity diagrams for LD-14, at different throw distances: 

One or two sided horizontal discharge: 

H1 (m) 

1 1.2 1.6 2 

LD-14 / 1 160 125 110 90 70 55 45 

LD-14 / 2 230 180 155 125 100 

LD-14 / 3 280 220 185 155 

LD-14 / 4 325 250 215 180 

2.5 

LD-14 / 1 160 125 110 90 70 55 45 

LD-14 / 2 230 180 155 125 100 

LD-14 / 3 280 220 185 155 

LD-14 / 4 325 250 215 180 

V H1 (m/s) 

0.4 

0.3 

0.25 

0.2 

V L (m/s) 

0.8 

0.6 

0.5 

0.4 

0.3 

0.25 

0.2 

0.15 

2 2.5 3 4 5 7 10 

A (m) 

0.15 

0.1 

2 2.5 3 4 5 7 10 

L (m) 

Alternate sided horizontal discharge: 

H1 (m) 

1 1.2 1.6 2 

LD-14 / 1 

LD-14 / 2 

160 

230 

125 110 90 

180 155 125 

70 

100 

55 45 

LD-14 / 3 340 280 220 185 155 

LD-14 / 4 395 325 250 215 180 

2.5 

LD-14 / 1 

LD-14 / 2 

160 

230 

125 

180 

110 90 

155 125 

70 

100 

55 45 

LD-14 / 3 340 280 220 185 155 

LD-14 / 4 395 325 250 215 180 

V H1 (m/s) 

0.3 

0.25 

0.2 

0.15 

0.1 

V (m/s) 

L 

0.7 

0.5 

0.4 

0.3 

0.25 

0.2 

0.15 

0.1 

2 2.5 3 4 5 7 10 

A (m) 

0.05 2 2.5 3 4 5 7 10 

L (m) 

170

p (Pa) 

t 


Sound power level and pressure drop: 

200 

100 

50 

20 

15 

10 

8 

6 

4 

3 

2 

1.5 

LD 13/1 LD 13/2 

20 

25 

30 

35 

40 

500 

L wA (dB(A) ) 

45 

50 

55 

1000 

1500 

2000 

p 

t 

(Pa) 

200 

100 

50 

20 

10 

8 

6 

4 

3 

2 

1.5 

10 

15 

20 

L wA (dB(A) ) 

25 

30 

35 

40 

500 

60 

55 

50 

45 

1000 

1500 

2000 

1 100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

1 100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

Correction factors applicable to LD-13/1 

Type of discharge vertical horizontal 

Flow rate control damper open closed open closed 

L=500 x 1 x 1,44 x 0,87 x 1,34 

L=1000 x 1 x 3,30 x 0,85 x 3,02 

L=1500 x 1 x 5,26 x 0,84 x 4,47 

L=2000 x 1 x 7,37 x 0,81 x 5,68 




L=500 x 1 x 1,91 x 0,86 x 1,79 

L=1000 x 1 x 5,91 x 0,70 x 5,31 

L=1500 x 1 x 9,88 x 0,58 x 8,67 

L=2000 x 1 x 14,10 x 0,47 x 11,99 

Example: 

Q = 150 m 3 /h 

L = 1000 mm 

Δp t = 14 Pa (vertical; damper closed) 

Δp t = 14 x 3,30 = 46,2 Pa (vertical; damper closed) 

Δp t = 14 x 0,85 = 11,9 Pa (horizontal; damper opened) 

Δp t = 14 x 3,02 = 42,3 Pa (horizontal; damper closed) 

L WA = 32 dB(A) 

Example: 

Q = 150 m 3 /h 

L = 500 mm 

Δp t = 22 Pa (vertical; damper opened) 




L WA = 30 dB(A) 

171

p (Pa) 

t 

t 



LD 13/3 LD 13/4 

200 

100 

50 

20 

10 

8 

6 

LwA (dB(A) ) 

20 

25 

30 

35 

500 

45 

40 

75 

70 

60 

50 

1000 

1500 

2000 

p (Pa) 

200 

100 

50 

20 

10 

8 

6 

L wA (dB(A) ) 

20 

25 

30 

35 

40 

500 

45 

55 

50 

1000 

1500 

2000 

4 

3 

2 

1.5 

1 

10 

15 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

4 

15 

3 

2 

10 

1.5 

1 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 




L=500 x 1 x 2,37 x 0,84 x 2,24 

L=1000 x 1 x 8,52 x 0,56 x 7,59 

L=1500 x 1 x 14,50 x 0,32 x 12,86 

L=2000 x 1 x 20,82 x 0,18 x 18,29 




L=500 x 1 x 3,08 x 0,70 x 2,91 

L=1000 x 1 x 11,07 x 0,47 x 9,87 

L=1500 x 1 x 18,85 x 0,27 x 16,72 

L=2000 x 1 x 27,07 x 0,15 x 23,78 

Example: 

Q = 300 m 3 /h 

L = 1000 mm 





L WA = 29 dB(A) 

Example: 

Q = 300 m 3 /h 

L = 500 mm 





L WA = 33 dB(A) 

172



t 

t 

p (Pa) 

200 

100 

50 

20 

10 

8 

6 

4 

3 

2 

1.5 

1 

LD 14/1 

15 

L wA (dB(A) ) 

20 

25 

30 

35 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

40 

45 

500 

50 

1000 

1500 

2000 

p (Pa) 

200 

100 

50 

20 

10 

8 

6 

4 

3 

2 

1.5 

1 

LD 14/2 

LwA (dB(A) ) 

15 

20 

25 

30 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

35 

40 

45 

500 

50 

1000 

1500 

2000 




L=500 x 1 x 1,81 x 0,76 x 1,31 

L=1000 x 1 x 3,83 x 0,42 x 3,23 

L=1500 x 1 x 5,80 x 0,28 x 5,11 

L=2000 x 1 x 7,87 x 0,19 x 7,07 




L=500 x 1 x 2,11 x 0,53 x 1,59 

L=1000 x 1 x 8,84 x 0,29 x 7,96 

L=1500 x 1 x 15,36 x 0,20 x 14,14 

L=2000 x 1 x 22,32 x 0,14 x 20,70 

Example: 

Q = 300 m 3 /h 

L = 1000 mm 





L WA = 38 dB(A) 

Example: 

Q = 300 m 3 /h 

L = 500 mm 





L WA = 36 dB(A) 

173

t 

t 



LD 14/3 LD 14/4 

200 

500 

200 

500 

p (Pa) 

100 

50 

20 

10 

8 

6 

4 

3 

2 

1.5 

1 

LwA (dB(A) ) 

15 

20 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

25 

30 

35 

40 45 50 

1000 

1500 

2000 

p (Pa) 

100 

50 

20 

LwA (dB(A) ) 

10 

25 

8 

6 

5 

20 

4 

3 

2 

1.5 

15 

1 

100 150 200 300 400 500 700 1000 

Q (m 3 /h) 

30 

35 

40 

1000 

1500 

2000 




L=500 x 1 x 2,41 x 0,33 x 1,87 

L=1000 x 1 x 13,86 x 0,19 x 12,69 

L=1500 x 1 x 24,92 x 0,16 x 23,17 

L=2000 x 1 x 36,76 x 0,13 x 31,33 




L=500 x 1 x 3,14 x 0,28 x 2,43 

L=1000 x 1 x 18,02 x 0,15 x 16,50 

L=1500 x 1 x 32,34 x 0,13 x 28,12 

L=2000 x 1 x 47,79 x 0,10 x 39,63 

Example: 

Q = 600 m 3 /h 

L = 1000 mm 





L WA = 38 dB(A) 

Example: 

Q = 600 m 3 /h 

L = 500 mm 





L WA = 36 dB(A) 

174

SLOT DIFFUSERS LD-15 

Slot diffuser LD-15 

RAL 

Application: 

Slot diffuser LD-15 is designed to supply air in 

rooms with floor to ceiling heights from 2.5 to 4m. 

They are primarily designed for the supply of cold 

air in applications with high comfort demands. 

80 

60 

CD 

Description: 

LD-15 slot diffuser is of a one-slot construction. 

The diffuser face plate consists of aluminium 

sections with built-in cylindrical deflectors made 

of recycled plastics. Individually adjustable 

deflectors allow continuous adjustment of 

discharge angle within the 360 0 range, as well as 

adjustment of air flow rate. The diffuser air flow 

can be completely shut by means of the cylindrical 

deflectors. The plenum box is made of galvanised 

sheet steel. 

Component Parts: 

1 Plenum box 


3 Main section 

4 Cylindrical air deflector 

205 

147 

2 

φ78 

No. of spigots 

1 

Standard lengths (L) 

300, 400, 500, 600, 700 

800, 900, 1000 

1100, 1200, 1300, 1400 

2 1500, 1600, 1700, 1800 

1900, 2000 

Position of inlet spigots 

41 

1 

3 

The positions of inlet spigots are equal to those of 

LD-13 and LD-14 slot diffusers. See diagram and 

table on page 164. 

7.5 

4 

Slot diffuser face plate designs 

Installation openings:15 x L (diffuser length) 

15 

Slot diffuser face plates are made of linear or 

angular ended sections, which allow the diffusers 

to be joined at different angles. Angular ended 

sections are not fitted with air direction controls. 

Cylindrical air deflectors 

Cylindrical deflectors are the most important components 

of a slot diffuser. They allow free adjustment 

of the air flow rate. 

Joining slot diffusers together in length 

Sections can be joint together by means of 

connecting plates. Total length of so joint sections 

is not limited. 

175

SLOT DIFFUSERS LD-15 

Fixing of the plenum box onto a LD-15 slot 

diffuser: 

• with self-tapping screws (designation U) 

• with spring clamps (designation S) 

Fixing of the diffuser to the plenum box 

with self-tapping screws (U) 

Fixing of the diffuser to the plenum box 

with a spring clamps (S) 

Installation methods: 

• Installation with suspension brackets on 

the plenum box (designation P) 

• Instalaltion with suspension brackets on the 

main section (designation R) 

Installation with suspension 

brackets on the plenum box (P) 

Installations with suspension bracket on the main section (R) 

Ordering key: 

LD-15/B/K/M/S/P/I L=1500 

I5 

I9 

I19 

P 

R 

Length L=300, 400, 500, 600 ..., 2000 (single piece) 


Sound and thermal insulation (from -40 o C to 105 o C), 9 mm thick, on the outside 

of the plenum box (synthetic rubber based material). 

Sound and thermal insulation (from -40 o C to 105 o C), 19 mm thick, on the 

outside of the plenum box (synthetic rubber based material). 

Installation of the diffuser with suspension brackets on the plenum box 

Installation with suspension brackets on the main section 


• Standard eloxal colour of the aluminium section 

is the original aluminium colour. Other colours 

shall be specified in the order. 

• When installing in cooling ceilings, consult the 

manufacturer. 

• Versions with insulation on the inside of the 

plenum box are also available. 

S 

U 

M 

K 

B 

W 

Fixing of the diffuser to the plenum box with a spring clamp 

Fixing of the diffuser to the plenum box with self-tapping screws 


Plenum box 



176

SLOT DIFFUSERS LD-15 TECHNICAL DATA 

Fast selection diagram: 

L=2000 

Technical data: 

Free surface, per 1 m of length: A ef =0.004559 m 2 . 

Air flow rate per 1 m of length: Q=20-70 m 3 /hm. 

L=1500 

L=1000 

L WA

200 

100 

500 

t 

SLOT DIFFUSERS LD-15 TECHNICAL DATA 

Sound power level and pressure drop 

55 

1000 

1500 

1000 

p (Pa) 

50 

20 

Lwa (dB(A)) 

35 

30 

45 

40 

50 

10 

6 

4 

3 

15 

20 

25 

2 

1.5 

1 

10 20 

10 

30 40 50 60 80 100 150 200 250 

Q (m 3 /h) 

α=0˚ α=45˚ α=90˚ 

Q (m 3 /h) 100 150 200 100 150 200 100 150 200 

L=500 Data in the diagram +5 +7 +10 +15 +32 +35 




ΔP t correction (in Pa) in cases of vertical 

discharge 

α = 0˚ Control damper in the inlet spigot is fully opened 

α = 45˚ Control damper in the inlet spigot is half opened 

α = 90˚ Control damper in the inlet spigot is fully closed 

α 

α=0˚ α=45˚ α=90˚ 

Q (m 3 /h) 100 150 200 100 150 200 100 150 200 





ΔP t correction (in Pa) in cases of inclined 

discharge 

α = 0˚ Control damper in the inlet spigot is fully opened 

α = 45˚ Control damper in the inlet spigot is half opened 

α = 90˚ Control damper in the inlet spigot is fully closed 

α 

178

FLOOR SLOT DIFFUSERS LD-16N 

RAL 

9010 

Floor Slot Diffusers LD-16N 

Application: 

LD-16N floor slot diffusers are a suitable solution 

for swimming pools and similar rooms with large 

glass surfaces and windows. They are designed for 

installation in the floor. Warm air is supplied in the 

upwards direction, towards the window. With 

appropriate dimensions, proper air supply is 

guaranteed, free of excessive draught or noise 

(L WA

FLOOR SLOT DIFFUSERS LD-16N INSTALLATION 

Installation method: 

max 0.2 m 

1 

2 

1 glass 

2 LD 16N slot diffuser 

3 air supply channel 

3 

Fast selection diagram: 

L wA < 35 dB(A); V ef =2,5 m/s; Δp t = 80 Pa/m 

25 

20 

LD-16 N /1 

v ef 

L D -16 

N/2 

L D -16 N/3 

L D -16N /4 

L D -16N /5 

Example 

The available floor area next to the glass surface 

is 15 m in length. The calculated supplied air flow 

rate is 4000 m 3 /h. From the diagram, the type: 

LD-16N/3 L=15m is selected. 

L D -16N/6 

15 

L (m) 

10 

Ordering key: 

5 

1000 2000 3000 4000 5000 6000 7000 8000 

Q (m 3 /h) 

LD-16N / 1 / L / n 

number of longitudinal sections (pieces) 

Q (m 3 /h) 

L WA (dB(A)) 

Δp t (Pa) 

L (m) 

v ef (m/s) 

Air flow rate 

Sound power level 

Pressure drop 

Slot diffuser length 

Effective air velocity 

Single piece length (L = 200, 300,......2000) 

1 

2 

3 

4 

5 

6 

LD-16N 


Floor slot diffuser 

Standard colour is RAL 9010. 

180

PANEL DESIGN SLOT DIFFUSERS LDP-13, 14 

St 

RAL 

Panel design slot diffusers LDP-13, 

LDP-14 

Application: 

Panel design slot diffusers are designed for the 

supply of air in rooms with floor to ceiling 

heights from 2.4 m to 4 m. They are suitable 

for supplying either cold or warm air. 

A 

Description: 

LDP-13 and LDP-14 consists of a diffuser face 

plate and a plenum box. The diffuser face plate is 

commonly made of sheet steel and its design 

can be suited to the customer’s requirements. 

Longitudinal guides, fitting tight to the sheet 

steel, are inserted in the diffuser face plate. 

Cylindrical deflectors, made of recycled plastics 

(ABS-antistatic) are installed in the guides, to 

allow free adjustment of both air jet discharge 

direction and flow rate. The number of slots per 

unit depends on the size of the unit. Diffuser face 

plate is powder painted in a RAL 9010 scale 

colour, or, on special orders, in other colours. 

The deflectors, equal to those of LD-13 or LD-14 

slot diffusers, are white or black as standard. 

The plenum box is made of galvanised sheet 

steel. It is fitted with a flow rate control damper, 

designed for fine air flow rate adjustment. 

1 

3 

Types: 

• LDP-13 m = 12 mm 

• LDP-14 m = 22 mm 

H 

9 

4 

2 

φ D 

Component parts: 

1 Plenum box 

2 Volume control damper 


4 Cross member 

5 Diffuser face plate 

6 Guide 

7 Air deflector 

8 Spring clamp 

5 C3 

8 

7 

6 

Dimensions: 

LDP-13 

LDP-14 

Size C3 Slot length A φ D H No. of slots h No. of slots h 

400 395 300 370 198 320 8 25 6 40 

500 495 400 470 198 320 10 6 

25 

600 595 500 570 248 380 12 25 8 

40 

625 620 500 570 248 380 12 8 

181

PANEL DESIGN SLOT DIFFUSERS LDP-13, 14 

Special orders: 

On special order, we can deliver diffuser face 

plates of any design. The shape and dimensions 

are specified in agreement with the designer or 

customer. 

Technical data: 

Tecnical data are determined upon the definition 

of the shape, design, number of discharge slots 

and other factors. 

Fast flow rate 

determination (at L WA < 35 dB(A)): 

LPD-13: flow rate per 1 meter length ≈100m 3 /h 

LPD-14: flow rate per 1 meter length ≈150m 3 /h 

Ordering key: 

LDP-13/B/K/M/I 

Size 400 

I5 

I9 

I19 

M 

Size (400, 500, 600, 625) 







K 

Plenum box 

B 

W 

LDP-13 

LDP-14 




• Versions with insulation on the inside of the plenum box are also available. 

182

ROUND DUCT DIFFUSER SKD-13 

St 

RAL 

9010 

Round Duct Diffuser SKD-13 

Application: 

Round duct diffusers SKD-13 are designed for supplying air to the rooms 

with large floor to ceiling heights, e.g. conference halls, gyms, industrial 

halls etc. They can be installed at any location within the duct network, 

which renders them suitable for supplying of either hot or cold air. 

The T register model is designed to control the supply air flow-rate at the 

individual diffuser level. The T register design is recommended for 

installations with several round duct diffusers in one line. In such cases, 

the flow-rates of the diffusers near the line beginning should be slightly 

reduced, in order to supply adequate amounts of air to the diffusers 

farther along the line. 

Description: 

The duct diffuser consists of galvanised round cross-section tubes with 

inserted longitudinal guides, fitting tight into the tubes. Cylindrical 

deflectors made of recycled plastics are inserted into the guides, to allow 

continuous adjustment of discharged air direction within the 360 o range. 

Diffusers are available with different number of slots. The tube is painted in 

a RAL 9010 scale colour, or, on special orders, in other colours. The 

deflectors, equal to those of LD-13 slot diffusers, are white or black as 

standard. 

A T register, black in colour, is inserted in the SKD-13D/T. The T register 

is adjusted by means of a PVC knob, screwed onto a threaded bar. 

3 2 1 

Dimensions: 

φD/no.of 2 4 6 8 10 12 14 

Slots Slots Slots Slots Slots Slots Slots Slots 

150 

160 

180 

200 

225 

250 

280 

300 

315 

355 

400 

450 

500 

560 

600 

630 

710 

800 

900 

Components: 

1. SKD-13D 

2. T-register 

3. T-register adjusting knob 

L D L L V 

/ 1000 800 

1505 750 2 X 500 

1755 875 2 X 600 

2005 1000 2 X 800 

Diffuser structure for lengths exceeding 1000 mm: 

A 

D 

φ 

60 L v 

60 

L 

Note: φ D is the diffuser internal diameter. 

60 

Lv 

L 

5 

Ld 

Lv 

L 

60 

183

ROUND DUCT DIFFUSER SKD-13 

Accessories: 

End cover 

Ød 

Joining piece 

Ød 

Note: φd is the external diameter. 

40 40 

φD 

40 20 

7 

Elbow 90 0 

Ød 

L 

r 

7 

40 

Size d L,r 

150 148.7-149.3 150 

160 158.7-159.3 160 

180 178.6-179.3 180 

200 198.6-199.3 200 

224 222.5-223.3 224 

250 248.5-249.3 250 

280 278.4-279.3 280 

300 298.4-299.3 300 

315 313.4-314.3 315 

355 353.3-354.3 355 

400 398.3-399.3 400 

450 448.2-449.3 450 

500 498.2-499.3 500 

560 558.1-559.3 560 

630 628.1-629.3 630 

710 708.0-709.3 710 

800 798.1-799.3 800 

900 897.0-899.3 900 

Installation of SKD-13/D: 

SKD-13/D 

Joining 

piece 

Tube 

Joining 

piece 

SKD-13/D 

L 

87 L 

87 

L 

60 

SKD-13/R 

SKD-13/R is constructed for installations into round ducts with square 

openings. 

H 

L L v H No. of øD of tube Installation openings 

slots L-35 H-35 

580 500 100 1 150-355 545 65 

680 600 150 2 355-900 645 115 

880 800 200 3 600-2400 845 165 

880 800 250 4 600-2400 845 215 

L v 

L 

Installation of SKD-13/R: 

184

ROUND DUCT DIFFUSER SKD-13 TECHNICAL DATA 

Ordering key for SKD-13D: 

Ordering key for SKD-13R: 

SKD-13D /B /T /φ 355 /2 L=1000 mm 

SKD-13R /B /T /φ355 /2 

L=680 mm, H=150 mm 

length 

B 

W 

number of slots 

tube diameter 

T-register 



tube 

length 

number of slots 

tube diameter 

T-register 

B Black deflectors 

W White deflectors 

R diffuser designed for 

installation into round 

ducts 


Example accessory specification: 

Accessory: Elbow 90 0 

Colour: RAL 9010 

Quantity: 1 piece 

185


Pressure drop determination diagram 

Fast selection diagram 

L WA 

< 35 dB(A) 


2 4 6 8 10 12 14 

Example 

Air flow rate: Q=250 m 3 /h 

Nominal size: 

450 mm 

Appropriate number of slots is: 4 

φ150 - φ250 

φ280 - φ355 

Nominal φ 

Air velocity in the duct v(m/s) 

ΔP t (Pa) 

Q (m 3 /h) 

Nominal size φ mm 

φ400 - φ450 

φ500 - φ900 

125 250 375 500 625 750 825 

Air flow rate (m 3 /hm) 

186


Pressure drop determination diagram 

v .......Air velocity in the duct 

Example 1 

Nominal size: φ 500 mm 


Air velocity in the duct: 4 m/s 

Flow rate through SKD: Q=450 m 3 /h 

Pressure drop: 15,5 Pa 

Example 2 

Max. pressure drop: 30 Pa 

Air velocity in the duct: 6 m/s 

Flow rate through SKD: Q=400 m 3 /h 

Unit to be chosen: SKD-13 φ400-900; n=8 

Pressure drop: 27 Pa; L WA

The right for technical changes reserved. 

188

zvezek 1 - ANG.indd - Hidria

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