Characteristics of an adjustable frame (or fireproof frame) should be considered when the building is in early phase of construction. This recommendation is based on fact that particular building aperture has to be adjusted for mounting of frame. Aperture adjastment should be done according to specifications mentioned bellow:
SIZES OF BUILDING APERTURE FOR ADJUSTABLE FRAME MOUNTING:
| Exact sizes of interior doors | Sizes of building aperture |
| 600 mm x 1970 mm | 690 mm + - 10 mm x 2020 mm + - 10 mm |
| 700 mm x 1970 mm | 790 mm + - 10 mm x 2020 mm + - 10 mm |
| 800 mm x 1970 mm | 890 mm + - 10 mm x 2020 mm + - 10 mm |
| 900 mm x 1970 mm | 990 mm + - 10 mm x 2020 mm + - 10 mm |
| 1000 mm x 1970 mm | 1090 mm + - 10 mm x 2020 mm + - 10 mm |
| 1100 mm x 1970 mm | 1190 mm + - 10 mm x 2020 mm + - 10 mm |
| 1250 mm x 1970 mm | 1350 mm + - 10 mm x 2020 mm + - 10 mm |
| 1450 mm x 1970 mm | 1550 mm + - 10 mm x 2020 mm + - 10 mm |
| 1600 mm x 1970 mm | 1700 mm + - 10 mm x 2020 mm + - 10 mm |
| 1650 mm x 1970 mm | 1750 mm + - 10 mm x 2020 mm + - 10 mm |
| 1800 mm x 1970 mm | 1900 mm + - 10 mm x 2020 mm + - 10 mm |
| 1850 mm x 1970 mm | 1950 mm + - 10 mm x 2020 mm + - 10 mm |
SIZES OF BUILDING APERTURE FOR FIREPROOF FRAME MOUNTING:
| Exact sizes of fireproof doors | Sizes of building aperture |
| 600 mm x 1970 mm | 710 mm + 5 mm x 2030 mm |
| 700 mm x 1970 mm | 810 mm + 5 mm x 2030 mm |
| 800 mm x 1970 mm | 910 mm + 5 mm x 2030 mm |
| 900 mm x 1970 mm | 1010 mm + 5 mm x 2030 mm |
| 1000 mm x 1970 mm | 1110 mm + 5 mm x 2030 mm |
| 1100 mm x 1970 mm | 1210 mm + 5 mm x 2030 mm |
| 1250 mm x 1970 mm | 1360 mm + 5 mm x 2030 mm |
| 1450 mm x 1970 mm | 1560 mm + 5 mm x 2030 mm |
| 1600 mm x 1970 mm | 1710 mm + 5 mm x 2030 mm |
| 1650 mm x 1970 mm | 1760 mm + 5 mm x 2030 mm |
| 1800 mm x 1970 mm | 1910 mm + 5 mm x 2030 mm |
| 1850 mm x 1970 mm | 1960 mm + 5 mm x 2030 mm |