Opening Sizes
Why so many access door opening sizes?
To be able to perform a large variety of tasks:
Inspection, cleaning, the replacement of components (dampers, filters, etc.), maintenance and repair work (i.e. fans), all these tasks require to have access into the ventilation air ducts. A large choice of access door openings help carrying through these operations as comfortably as possible. One must even consider that workers might have to enter into the air ducts!
External restrictions and requirements:
Nearby air ducts or walls might hinder the access. Larger openings, or even a different opening shape, could facilitate the access. Also, the openings must allow the insertion many types of objects or equipment (cleaning robots, dampers, spare parts, etc.).
Stability of the air duct:
Large openings can adversely affect the stability of the air duct. This aspect should be considered when selecting the access door sizes (DIN EN 12097)
The above aspects are often underestimated, but make a big difference on the construction site!
How many access door opening dimensions are there?
METU offers eleven access door opening sizes for rectangular air-ducts and five opeing sizes for round ducts or the curved part of oval ducts.
Dimensions (A / B / R)
RD 18 : 80 mm / 180 mm / 40 mm
RD 21 : 100 mm / 200 mm / 50 mm
RD 315 : 150 mm / 300 mm / 75 mm
RD 32 : 200 mm / 300 mm / 100 mm
RD 42 : 200 mm / 400 mm / 100 mm
RD 43 : 300 mm / 400 mm / 150 mm
RD 53 : 300 mm / 500 mm / 150 mm
RD 54 : 400 mm / 500 mm / 200 mm
RD 64 : 400 mm / 600 mm / 200 mm
RD 65 : 500 mm / 600 mm / 250 mm
RD 75 : 500 mm / 700 mm / 250 mm
RRD 18 : 76 mm / 182 mm / 38 mm
RRD 21 : 97 mm / 200 mm / 48,5 mm
RRD 32 : 194 mm / 298 mm / 97 mm
RRD 43 : 290 mm / 400 mm / 145 mm
RRD 54 : 390 mm / 496 mm / 195 mm
Dimensions when the template lays on a flat surface.
All the above mentioned opening dimensions are might not be available depending on the access door types and/or the materials.
Available dimensions for the access doors with NBR gasket (liquid-tight version)
RRD 18 (180 × 80 mm) with NBR for Duct-Ø from 96 up to 1000 mm,
RRD 21 (200 × 100 mm) with NBR for Duct-Ø from 130 up to 1000 mm, and
RRD 32 (300 Ø 200 mm) with NBR for Duct-Ø from 260 up to 1000 mm.
These access doors have been specially designed for the METU-FORM air ducts and are not suitable for spiral ducts.
The self-adhesive part of the templates contains some silicone. Please also refer to the information about PWIS: ZI-102.
