Building Services (CE-703 (D)) - Unit 1 Short Notes

UNIT 1: BUILDING SERVICES

I. BUILDING CODES, STANDARDS & CLASSIFICATIONS

National Building Code (NBC) of India

• Published by the Bureau of Indian Standards (BIS).

• Provides unified regulatory framework for building construction, safety, and services across India.

• Classification of Buildings (as per NBC Part 4):

  | Group | Type | Description | Examples | | :--- | :--- | :--- | :--- | | A | Residential | Buildings for living. | Lodging houses, dormitories, flats. | | B | Educational | Schools, colleges. | Up to 8th standard (B-1), above (B-2). | | C | Institutional | Healthcare, care homes. | Hospitals, nursing homes, orphanages. | | D | Assembly | Public gatherings. | Theatres, cinemas, auditoriums, stadia. | | E | Business | Offices, banks. | Offices, public libraries, courts. | | F | Mercantile | Shops, markets. | Departmental stores, shops (<1000 m²). | | G | Industrial | Manufacturing, processing. | Factories, workshops, power plants. | | H | Storage | Warehouses, depots. | Godowns, cold storage, grain silos. | | I | Hazardous | Storage/use of hazardous materials. | Petrol pumps, LPG godowns, chemical plants. |

Classification of Fire (Modes of Fire)

Based on the nature of combustible material:

[!TIP] Exam Focus: NBC classification and Fire classes are very frequently asked in short notes (3-4m). Memorize the groups and fire classes with one clear example each.

Lift Codes and Standards

• Primary Indian Standard: IS 14665 (Parts 1 to 4) - Code for safety of lifts and escalators.

• Other relevant IS: IS 15259 (lift well & machine room dimensions), IS 15750 (safety rules).

• Codes cover design, installation, operation, maintenance, and safety gear testing.

General Safety Precautions in Lifts

• Regular maintenance and statutory inspections.

• Functional safety gears (governor, safety clamps, buffers).

• Emergency alarm and communication system.

• Proper lighting and ventilation in car & well.

• Fire-resistant lift well & machine room enclosures.

• Emergency power for rescue operation.

• Load indication and over-load alarm.

• Trained and licensed operators/attendants (where required).

II. VERTICAL TRANSPORTATION SYSTEMS

Lifts (Elevators)

• Classification:

  • By Use: Passenger, Goods/Freight, Hospital, Service, Dumbwaiter.

  • By Speed: Low-speed (<1 m/s), Medium-speed (1-2.5 m/s), High-speed (>2.5 m/s).

  • By Drive: Hydraulic, Electric (Traction).

• Types of Lift Operation:

  | Type | Principle | Best For | | :--- | :--- | :--- | | Selective | Car answers all calls in its direction of travel. | Low-rise, low-traffic buildings. | | Collective | Car stores all landing calls when full, answers in sequence. | Medium-rise, moderate traffic. | | Collective Selective | Combines both: stores calls when full, selects next. | High-rise, heavy traffic (most common). | | Group Control | Central computer controls multiple cars as a group. | Very high-rise, complex buildings. |

• Lift Control Systems:

  • Relay-Based (Electromechanical): Older systems using physical relays.

  • Microprocessor-Based (Solid-State): Modern, flexible, programmable, supports group control & monitoring.

  • Working: Call registration → car selection → direction decision → door operation → floor arrival.

• Traffic Analysis & Selection (Calculation of Requirements)

  • Key Parameters:

    • Population (P): Estimated number of people in the building.

    • Peak Up-Traffic (Peak 5-min): % of population arriving in peak 5-min (e.g., 15% for offices).

    • Average Car Capacity (C): Persons per trip (e.g., 13 for 1000 kg car).

    • Round Trip Time (RTT): Time for one complete trip (loading, travel, unloading, return).

    • Interval (Int): Average time between successive car arrivals at main lobby. Int = RTT / n (n = no. of cars).

  • Design Criterion: Interval should be 20-30 seconds for good service.

  • Estimation: Use Round Trip Time (RTT) formulas based on building height, speed, acceleration, door times.

  • Number of Lifts (n): n = RTT / Desired Interval.

• Safety Precautions & Codes: (See Section I & III for cross-reference).

• Fire Safety Provisions in Lifts:

  • Fireman's Switch: In lobby, overrides normal control, takes car to designated floor.

  • Phase-I & Phase-II Operation: Recall to fire-recall floor (usually ground/2nd below) with doors open.

  • Fire-resistant construction of well, machine room, and car.

  • Emergency power for operation during fire.

Escalators

• Working Mechanism & Components:

  • Motor-driven: Electric motor drives gearbox → drives step chain (continuous loop).

  • Steps: Roll on tracks, remain horizontal.

  • Handrail: Driven synchronously with steps for passenger support.

  • Comb Plates: Transition plates at top/bottom.

  • Safety Devices: Step gap sensors, handrail entry sensors, emergency stop buttons.

• Comparison with Lifts:

  | Feature | Lift | Escalator | | :--- | :--- | :--- | | Primary Use | Vertical transport over many floors. | Short vertical distances (2-5 floors). | | Capacity | High per trip, but intermittent. | Continuous flow, lower instantaneous capacity. | | Space | Requires deep well & machine room. | Requires long inclined shaft. | | Speed | Fast (2-3 m/s). | Slow (~0.5 m/s). | | Energy Use | Intermittent. | Continuous when running. | | Safety in Fire | Can be recalled to floor. | Must be shut down (acts as flue). |

Travelators (Moving Walkways)

• Horizontal or slightly inclined (≤12°) conveyor for moving people over short distances (e.g., airports, malls).

• Similar mechanism to escalator but with flat pallets/comb plates.

• Used for circulation within a floor or between adjacent buildings.

III. FIRE SAFETY & PROTECTION SYSTEMS

Fire Hydrants

• Definition: Outlet connection provided in a building for fire department to pump water into the building's internal fire fighting system.

• Components: Hydrant body, outlet nozzle (63 mm or 100 mm), valve, spindle, spindle nut, cap with chain.

• Installation Provisions (NBC):

  • Located in staircase lobbies or corridors.

  • Max distance from any point: 30 m (for first hose, 60 m for second).

  • Hose Cabinet: Must house hose, nozzle, and branch pipe. Clear signage.

  • Hydrant Riser: Minimum 2 nos. of 100 mm dia. risers with landing valves every floor.

  • Pump & Pressure: Jockey pump for maintenance pressure, main fire pump for required flow & pressure.

Fire Protection Requirements for High-Rise Buildings (NBC)

• Refuge Floors: Every 7-10 floors (max 22m apart). Fire-resistance rating 2 hrs. Separate ventilation.

• Fire Lifts: Dedicated lifts with fireman's switch, independent power supply, 2-hr fire-rated enclosure.

• Staircases: At least 2, enclosed, pressurised, fire-resistant (2 hrs). Separate from service ducts.

• Fire Alarm System: Automatic detection (smoke/heat) + manual call points + audio-visual alerts.

• Fire Compartmentalisation: Fire walls, fire doors to limit spread.

• External Access: Fire engine access, fire lift lobby at ground.

Fire Fighting Systems

• Common Causes of Fire: Electrical faults, cooking, smoking, heating equipment, flammable liquids, arson.

• Carbon Dioxide (CO₂) Storing System:

  • Use: For electrical fires (Class E) and flammable liquids (Class B) in enclosed spaces (server rooms, transformer rooms, paint shops).

  • Working: CO₂ stored under pressure in cylinders. On detection, released into protected volume via nozzles. Displaces oxygen (asphyxiation) and cools slightly.

  • Advantages: Clean, non-conductive, no residue. Disadvantages: Asphyxiation hazard, requires sealed enclosure.

• Working Fire Control Systems:

  • Wet Riser: Pipes permanently filled with water under pressure. For buildings below 30m. Simple, instant supply.

  • Dry Riser: Pipes empty (dry) until charged by fire department. For buildings above 30m. Prevents freezing. Requires landing valves on each floor.

• Other Systems:

  • Automatic Sprinklers: Heat-sensitive element (glass bulb) bursts, water sprays over fire area. Can be wet, dry, deluge, or pre-action type.

  • Foam Systems: For high-hazard flammable liquid fires (Class B). Foam concentrate mixed with water, forms blanket.

Escape Routes and Means of Egress

• Fire Escapes: External staircases or balconies for emergency exit. Must be direct, unobstructed, well-lit, and have fire-resistant construction.

• Service Duct Escape Routes: Ducts for pipes/cables can act as vertical shafts for fire spread. Must have:

  • Fire-stopping at every floor penetration.

  • Access doors with fire-resistance rating.

  • Can be used as alternative escape route only if specifically designed & approved.

Fire Safety Provisions in Lifts (Cross-referenced from II)

• As detailed in Section II (Fireman's Switch, Phase-I/II, fire-rated enclosures, emergency power).

IV. WATER SUPPLY, TREATMENT & PLUMBING

Water Supply Systems for Multistoried Buildings

Types of Water Supply Pipes (Materials)

• GI (Galvanised Iron): Traditional, strong, but corrodes, heavy.

• CI (Cast Iron): Durable, good for underground, heavy.

• HDPE (High-Density Polyethylene): Flexible, corrosion-free, joints by fusion, popular now.

• PVC/UPVC: Rigid, cheap, good for drainage & cold water, not for hot water.

• CPVC: Chlorinated PVC, suitable for hot & cold water.

• PEX: Cross-linked polyethylene, flexible, good for hot water, freeze-resistant.

Water Supply Fixtures and Appliances

• Fixtures: Taps, faucets, showers, bibcocks, stop valves.

• Appliances: Water closets (WC), basins (sinks), urinals, bathtubs, drinking fountains.

• Requirements: Adequate flow rate, proper drainage connection, ease of cleaning, durability.

Piping Systems (General Considerations)

• Layout: Shortest route, avoid sharp bends, adequate slope for drainage.

• Sizing: Based on fixture units (Hunter's curve) & demand.

• Support & Expansion: Proper hangers/supports, expansion loops/joints for thermal movement.

• Insulation: For cold water (condensation) and hot water (heat loss).

• Accessibility: Valves, cleanouts must be accessible.

Swimming Pool Water Treatment

• Disinfection By-Product (DBP) Mitigation:

  • DBPs (e.g., trihalomethanes) form when chlorine reacts with organic matter (sweat, urine).

  • Measures: Pre-swim shower (reduce organics), maintain proper C:T ratio (Concentration x Time), use secondary disinfectants (UV, Ozone) to reduce chlorine dose, good filtration to remove precursors.

• Algae Control Methods:

  • Chemical: Algaecides (copper-based, quaternary ammonium compounds).

  • Physical: Brushing pool surfaces, vacuuming.

  • Operational: Maintain free chlorine residual (1-3 ppm), proper pH (7.2-7.8), good circulation & filtration, cover pool when not in use.

V. HEATING, VENTILATION & AIR CONDITIONING (HVAC) & THERMAL COMFORT

Ventilation Systems

Air Conditioning Systems

• Essentials of an AC System:

  1. Cooling Load: Heat to be removed (W or BTU/hr).

  2. Refrigeration Cycle: Evaporator (absorbs heat), Compressor, Condenser (rejects heat), Expansion valve.

  3. Air Handling: Supply & return air fans, filters, cooling coil.

  4. Distribution: Ducts, diffusers.

  5. Controls: Thermostat, humidistat.

• Difference between Unitary and Central AC:

  | Feature | Unitary (Split/Window) | Central (Packaged/VRF) | | :--- | :--- | :--- | | System | Self-contained, one unit per space. | Central plant serves multiple spaces. | | Initial Cost | Low per unit. | High initial cost. | | Control | Individual per room. | Centralised/zonal control. | | Maintenance | Simple, distributed. | Complex, centralised. | | Aesthetics | Indoor unit visible. | Ducted, concealed. |

• Types of AC Systems:

  • Window AC: All components in one box.

  • Split AC: Separate indoor (evaporator) & outdoor (condenser) units.

  • Packaged AC: All components in one cabinet (rooftop/ground), serves multiple rooms via ducts.

  • VRF/VRV: Variable refrigerant flow. Multiple indoor units, one outdoor. Individual control, energy efficient.

  • Central Chilled Water Plant: Central chiller cools water, pumped to AHUs (Air Handling Units) in buildings.

Thermal Insulation

• Methods of Thermal Insulation:

  • Bulk/Blanket: Fibrous mats (glass wool, rock wool) - traps air.

  • Rigid Board: Foam boards (EPS, XPS, PIR) - high R-value, moisture resistant.

  • Loose Fill: Cellulose, vermiculite - for irregular spaces.

  • Reflective: Aluminium foils - reflect radiant heat (used in roofs).

  • Insulating Plasters/Render: For walls.

• Thermal Insulation of Walls:

  • External Insulation (ETICS): Best performance, reduces thermal bridges. Insulation board on outer wall, protected by render.

  • Internal Insulation: Easier, but causes thermal bridges, reduces internal space.

  • Cavity Wall Insulation: Fill cavity with insulating material (beads, foam).

  • Insulating Blocks: Use lightweight concrete blocks with good insulation.

VI. ACOUSTICS & NOISE CONTROL

Materials and Requirements for Good Acoustics

• Requirements: Adequate loudness, clarity, intimacy, ambience, uniform distribution, adequate reverberation.

• Materials:

  • Absorbers: Porous (fabric, carpet, acoustic tiles), resonant (perforated panels with cavity), membrane (thin sheets over air gap).

  • Reflectors: Hard, smooth surfaces (plaster, wood, glass) to direct sound.

  • Diffusers: Irregular surfaces (wood slats, polycylindrical) to scatter sound, reduce echoes.

Acoustic Design of an Auditorium (Factors)

1. Shape: Shoebox, arena, fan-shaped - affects sightlines & sound distribution.

2. Volume: Per person (6-9 m³/person for speech, 9-12 for music).

3. Reverberation Time (RT): Optimised for use (speech: 0.7-1.1s, music: 1.5-2.5s).

4. Seating Layout & Aisle Design: For sightlines & sound.

5. Ceiling Design: Reflectors, clouds, absorbers placed strategically.

6. Wall & Floor Materials: Balance absorption & reflection.

7. Background Noise Level: <30 dB(A) for concert halls.

8. Sound Insulation: From outside noise & between halls.

Reverberation Time (RT)

• Definition: Time (in seconds) for sound to decay by 60 dB after sound source stops.

• Significance: Determines clarity & loudness. Too long = muddy, too short = dead.

• Calculation (Sabine's Formula):

$$RT_{60} = \frac{0.161 V}{A}$$

Where:

*   $V$ = Volume of room (m³)

*   $A$ = Total absorption (sabins) = $$\displaystyle \sum (S_i \cdot \alpha_i) $$

*   $$\displaystyle S_i $$ = Surface area of material i (m²)

*   $$\displaystyle \alpha_i $$ = Absorption coefficient of material i

\boxed{RT_{60} = \frac{0.161 V}{\sum (S_i \cdot \alpha_i)}}

[!TIP] Exam Focus: Sabine's formula is a sure-shot question (4m). Memorise variables and units. Also know Eyring's formula for highly absorbent rooms.

Noise Rating (NR) Curve

• Graphical standard (ISO/IS) defining acceptable indoor noise levels across octave bands (63 Hz to 8 kHz).

• Each curve (NR 20, 25, 30...) gives max permissible sound pressure level (dB) for each frequency.

• Used for designing HVAC systems, plant rooms, and assessing building services noise.

• Application: Select equipment (fans, pumps) that meets required NR curve for the space (e.g., NR 30 for offices, NR 25 for libraries).

Sources of Noise in Buildings

• External: Traffic, aircraft, industry, neighbours.

• Internal:

  • Building Services: HVAC (fans, ducts, diffusers), plumbing (water hammer, pumps), lifts, electrical (transformers, generators).

  • Human Activity: Speech, movement, music.

  • Equipment: Office machines, kitchen appliances.

Noise Control at the Planning Stage

1. Site Selection: Away from noise sources.

2. Building Layout: Place noisy areas (plant rooms, staircases) away from quiet areas (bedrooms, conference rooms).

3. Zoning: Separate service shafts from occupied spaces.

4. Façade Design: Use double-glazed windows, solid walls, avoid direct line-of-sight to noise source.

5. Structure: Massive floors/walls for impact insulation.

Sound Insulation of Walls (Construction Techniques)

• Mass Law: Heavier wall = better insulation. Increase surface density (kg/m²).

• Cavity Walls: Two leaves with air gap (min 50mm) - decouples vibration.

• Double Leaf with Absorbent: Cavity filled with mineral wool.

• Staggered Stud: Studs not aligned, reduces flanking transmission.

• Resilient Channels: Mount one leaf on resilient mounts to break contact.

• Plasterboard Layers: Multiple layers with damping compound.

VII. SUSTAINABILITY, GREEN BUILDING & LANDSCAPE

Green Building Concerns and Concepts

• Energy Efficiency: High-performance envelope, efficient HVAC & lighting, renewable energy.

• Water Conservation: Low-flow fixtures, rainwater harvesting, wastewater treatment & reuse.

• Material Efficiency: Use of recycled, local, rapidly renewable materials; waste reduction.

• Indoor Environmental Quality (IEQ): Good ventilation, daylight, low-VOC materials, thermal comfort.

• Site Sustainability: Reduce disturbance, manage stormwater, promote biodiversity.

• Certification Systems: LEED (US), GRIHA (India), BREEAM (UK).

Rainwater Harvesting (RWH)

• Systems:

  • Rooftop RWH: Catchment (roof) → Conduits → First Flush (diverts first dirty runoff) → Filter (sand, gravel, charcoal) → Storage Tank (underground/overhead) → Usage (flushing, gardening) or Recharge (borewell/seepage pit).

  • Surface Runoff RWH: Catchment (paved area) → Check dams, percolation pits, recharge wells.

• Design Considerations: Catchment area, rainfall intensity (from IMD data), storage capacity (for 1-3 dry months), water quality, end use.

Solar Energy Systems (with sketches)

• Solar Water Heating (SWH):

  • Components: Solar thermal collector (flat plate/evacuated tube), insulated storage tank, circulating pump (active) or thermosyphon (passive).

  • Working: Sun heats collector fluid → transfers heat to tank water via heat exchanger or directly in thermosyphon.

  • Sketch: Show collector on roof, tank above/below, piping loop.

• Solar Photovoltaic (PV):

  • Components: PV modules (panels), mounting structure, inverter (DC to AC), battery (optional), charge controller.

  • Working: Sunlight → PV cells generate DC electricity → inverter converts to AC for use/grid feed.

  • Sketch: Show panels on roof, inverter, distribution board.

Landscaping and Horticulture in Building Context

• Functions: Aesthetic, microclimate control (shade, cooling via evapotranspiration), air purification, noise reduction, stormwater management, habitat creation.

• Design Considerations: Native/drought-resistant plants, soil type, irrigation (drip), shade trees on south/west, green roofs/walls, hardscape vs softscape balance.

Refuse Collection Systems in Buildings

• Centralised Collection: Common bins on each floor/chute → centralised storage room → municipal collection.

• Decentralised: Individual bins in each apartment/office → collected by building staff → central storage.

• Chute System: Garbage chutes (vertical) from each floor to central collection room (common in high-rises). Requires fire-stop at each floor, regular cleaning, pest control.

• Segregation at Source: Bins for wet (biodegradable), dry (recyclables), hazardous waste.

VIII. BUILDING PLANNING, DESIGN & SECURITY

Design of Specific Building Types/Elements

• Open-Air Theatre:

  • Stage: Raised, with proper depth, wing space, backstage.

  • Audience Area: Sloped seating (raked) for sightlines. Seating angle 100-110°.

  • Acoustics: Reflective canopy/shell over stage, absorptive rear wall, minimal echoes.

  • Circulation: Separate entry/exit for audience & performers.

  • Back-of-House: Dressing rooms, storage, workshops.

• Car Parking Systems:

  • Surface Parking: Simple, low cost, large land area.

  • Multi-Storey Parking: Ramps (helical, straight) or mechanical lifts.

  • Mechanical/Automated Parking: Stackers, puzzle systems, rotary. High density, space-saving, costly.

  • Design Considerations: Turning radius (6m min), bay size (2.5m x 5.5m), ramp slope (1:6 to 1:10), clear height, ventilation, lighting, security.

Building Services in Complexes

• Essential Services: Water supply, Sewage & Drainage, Electrical (power & lighting), HVAC, Fire fighting & alarm, Lifts & escalators, Communication (telephone, data, PA).

• Specialised Services: Solar systems, BMS (Building Management System), Security (CCTV, access control), Waste management, Landscaping irrigation.

Access Control Systems in Building Security

1. Key-based: Traditional locks & keys (least secure).

2. Card-based: Proximity cards (RFID), magnetic stripe cards.

3. Biometric: Fingerprint, iris, facial recognition (high security).

4. Keypad/PIN: Numeric code entry.

5. Combination: Card + PIN, biometric + card (2-factor).

6. Vehicle Access: Boom barriers with RFID tags.

IX. SUPERVISION, ADMINISTRATION & MANAGEMENT

Administrative Functions of Supervisors (in building services context)

1. Planning & Scheduling: Plan maintenance schedules, work assignments, resource allocation (manpower, materials).

2. Organising & Coordinating: Coordinate between different trades (electrical, plumbing, HVAC), manage subcontractors, ensure smooth workflow.

3. Staff Management: Supervise technicians/mechanics, impart training, monitor performance, handle grievances.

4. Budget & Cost Control: Estimate costs, monitor expenditure, control wastage, manage inventory of spares.

5. Quality Assurance: Ensure workmanship & materials meet specifications & codes, conduct inspections.

6. Safety & Compliance: Enforce safety rules (PPE, permits), ensure compliance with building codes & regulations.

7. Documentation & Reporting: Maintain logs, prepare reports on breakdowns, maintenance, incidents.

8. Problem Solving & Decision Making: Troubleshoot breakdowns, make operational decisions during emergencies.

[!TIP] Exam Focus: Administrative functions (7m) and fire safety provisions in lifts (7m) are very common. Be prepared to write 8-10 points with brief explanations. For calculations (lift traffic, RT), practice numerical problems from past papers.