Hi-Hatch ATCeiling Access Hatch

Single frame type with outer frame hidden. Excellent airtightness performance by setting packing on outer frame.
450×450, 600×600

Installation Location

  • Ceiling

Main Features

  • Single Frame with Outer Frame Hidden
  • A-4 Grade Airtightness Performance (When Sealing)
  • Can after Construction
  • Can Install into Wooden Frame
  • (Corp.) Public Buildings Association Evaluating Product (only When Using the Channel Catch)



  • 450×450(mm)
  • 600×600(mm)

Opening and Closing Part

  • Standard Type

  • Key Type (Key P301)

    Can Key Sharing with SD, DX, MOD

Color Variation

  • Silver Color


Airtightness Performance


Test Standard JIS A 1516-1994
Test Model: HHAT-454・606

*In order to confirm the airtightness of the frame itself, sealed the ceiling material, the inner frame and the outer frame. (Certain airtight performance cannot be demonstrated without sealing.)

Test Results

A-4 Grade

Airtightness grade and airtightness grading line conform to JIS A 4706 (sash).

*Data are our test values and not guaranteed values.



Outer Frame, Inner Frame/ Extruded Aluminum A6063S-t5 Anodized (Urethane Coating Available)

Model No. / Dimensions

□450 □600
Model No. Standard Type HHAT-454 HHAT-606
Key Type HHAT-K454 HHAT-K606
Dimensions Standard Dimensions 454×454 606×606
Ceiling Opening Dimensions 455×455 607×607
Inner Finishing Board Dimensions 433×433 585×585
Inner Backing Board Dimensions 407×407 559×559


Channel Catch

(Corp.) Public Buildings Association Evaluating Product (only When Using the Channel Catch)

Hanging Wire

To prevent falling inner frame by hanging the wire to inner frame and channel. Use it with spring hook attaches to (rotating axis side) the hole of inner frame.

For Square Stud Method “Z Screw”

Square stud method is construction technique using square stud differ from general construction steel-made ceiling base.

“Z screw” is NAKA Corporation’s original screw to fasten ceiling access hatch and square stud. There are some cases cannot available according to the combination of square stud method.

Urethane Coating (Custom-Made Finishing) Available



Hanger Hook

Use hanger hook.