--- title: "Functions of openings; door and window types" subject: "Building Technology" chapter: 6 key: "semester_6/building_technology:openings-functions-working" source: https://www.bctengineer.com/q/semester_6/building_technology/openings-functions-working site: BCT Engineering --- # Functions of openings; door and window types Building Technology · Chapter 6: Doors and windows - Asked in: 2067 Asar (old course), 2+3+3 marks - Video: [Types of Door (Part-1) | Classification of Doors | opening fixation in Building Construction](https://www.youtube.com/watch?v=9ysmz8msMak) — Decent T&C - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/building_technology/openings-functions-working - Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-6 ## Question What are the functions of openings? Explain any two types of door and window based on working operation with neat line sketches. ## Short answer Openings provide entry/exit, light, ventilation, privacy, security, view, and emergency escape. Sliding doors move sideways on tracks, saving space. Revolving doors rotate on a central pivot, maintaining air conditioning. Casement windows are side-hinged and swing open fully. Sliding windows move horizontally in grooves, needing no swing space but only half opens. ## Answer Openings are the doors, windows and ventilators left in a wall. #### Functions of openings - Entry, exit and movement between rooms (doors). - Natural light and ventilation (windows, ventilators). - Privacy, security and protection against rain, wind, noise and dust. - View of the outside and good appearance. - Emergency escape in a fire. #### Doors by working operation **1. Sliding door:** The shutter slides sideways on rollers along a top (or bottom) track, parallel to the wall. It needs no swing space, so it is used for shops, garages and wardrobes. ```text wall +==============+==============+ | fixed |<-- sliding | | | leaf | track ================================= ``` **2. Revolving door:** Three or four leaves fixed to a central pillar rotate inside a cylindrical enclosure. It keeps the air-conditioned air in and handles heavy traffic (hotels, banks). ```text wall | leaf ----+--/-- ( + ) top view: leaves turn ----+--\-- about central pivot ``` #### Windows by working operation **1. Casement (side-hung) window:** The sashes are hinged at the side and swing in or out like doors. It is the most common type and gives a full opening. ```text +-------+-------+ | sash | sash | hinges at the | -> | <- | outer posts +-------+-------+ ``` **2. Sliding window:** The sashes slide horizontally in grooves of the frame (aluminium/UPVC). It needs no swing space, but only half the opening can be open at a time. ```text +-----------+-----------+ | outer | inner | | sash <--|--> sash | sashes slide in | | | parallel grooves +===========+===========+ bottom track / groove ``` **Others:** pivoted, double-hung, louvred, fixed, bay and dormer windows. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why is a sliding door chosen? A. It gives maximum air flow B. It is the cheapest C. It keeps air-conditioning in D. It needs no swing space Answer: D. It slides on a track parallel to the wall. (Key point: Sliding door) 2. How does a revolving door work? A. Leaves rotate about a central pillar inside a cylindrical enclosure B. Leaves slide on rollers C. Leaves fold hinged together D. Leaves swing both ways on springs Answer: A. Three or four leaves turn on a central pivot. (Key point: Revolving door) 3. Where are casement window sashes hinged? A. At the top only B. At the sides, swinging like doors C. On a central pivot D. In grooves sliding horizontally Answer: B. Casement windows are side-hung and give full opening. (Key point: Casement) 4. What is a limitation of the sliding window? A. It needs large swing space B. It admits no light C. Only half the opening can be open at a time D. It cannot use aluminium Answer: C. Sashes slide over each other so half is open. (Key point: Sliding window limit) ## Related in Building Technology - [Functions of door and window; battened door elevation](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-window-functions-battened) — Building Technology, chapter 6 - [Door/window parts; casement, awning, hopper](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-window-parts-casement) — Building Technology, chapter 6 - [Door/window components and door types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-window-components-types) — Building Technology, chapter 6 - [Air flow through openings numerical (0.36 m, 0.4 m)](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aairflow-078p) — Building Technology, chapter 1, asked 2× - [Elements of battened door shutter](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Abattened-door-elements) — Building Technology, chapter 6, asked 2× - [Types of doors by working mechanism](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-types-working) — Building Technology, chapter 6, asked 2× ## Related in other subjects - [Rate analysis: sal wood door/window frame per m³](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Arate-sal-wood-frame) — Estimating and Costing, chapter 4, asked 3× - [Two-room building: brick plinth, door shutters, plaster](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-m-two-room-three-items) — Estimating and Costing, chapter 6 - [Characteristics of different window functions](https://www.bctengineer.com/question.md?key=semester_7%2Fdigital_signal_analysis_and_processing%3Awindow-characteristics) — Digital Signal Analysis and Processing, chapter 5 - [Cohen-Sutherland: two lines vs window A-D](https://www.bctengineer.com/question.md?key=semester_5%2Fcomputer_graphics%3Acohen-sutherland-two-lines-window-a) — Computer Graphics, chapter 3