Building Services (CE-703 (D)) - Unit 2 Short Notes

UNIT 2: BUILDING SERVICES

I. VERTICAL & HORIZONTAL TRANSPORTATION SYSTEMS

A. Lifts (Elevators)

1. Classification of Lifts

2. Types of Lift Operation

• Collective: Buttons for all floors; car stops at all registered calls in sequence.

• Selective: Calls are registered in order of floor position (up/down).

• Automatic: No attendant; push-button operation.

• Group Control: Microprocessor manages multiple cars as a system to optimize traffic.

3. Lift Control Systems

• Relay-Based: Older, electromechanical.

• Microcomputer/PLC: Modern, programmable, efficient.

• Group Control: Uses algorithms (e.g., "estimated time of arrival") to assign calls to the most suitable car.

4. Traffic Analysis & Lift Calculation

• Key Parameters:

  • Population (P): Number of persons in building.

  • Peak Demand: % of population using lifts in 5-min peak (e.g., 15% for offices).

  • Handling Capacity (Q): Persons moved in 5 mins. Q = (R × 100 × T) / (P × 300) where R=round trips, T=car capacity.

  • Interval (INT): Average time between successive car arrivals at main floor. INT = (R × 300) / (P × 100) seconds.

  • RTT (Round Trip Time): Time for one complete trip (load, travel, unload, return). Calculated via Baseline Method.

• Selection: Choose number of lifts & capacity to meet required Interval (e.g., <25s for offices) and Handling Capacity.

5. Safety Precautions & Codes

• IS Standards: IS 14665 (Parts 1-4) covers safety, installations, components.

• NBC (Part 4): Mandates shaft pressurization, firefighter's lift, recall switch.

• Precautions: Over-speed governor, safety gear, buffers, door interlocks, emergency alarm, communication.

6. Fire Safety Provisions for Lifts

• Firefighter's Lift: Dedicated lift with Phase I & II operation, fire service access.

• Recall Switch: At fire control room; sends all lifts to designated floor (usually ground) and holds doors open.

• Shaft Pressurization: Prevents smoke ingress into lift lobby & shaft.

• Lobby Requirements: 2-hour fire-rated enclosure, positive pressure.

[!TIP] Exam Focus: Be prepared to calculate RTT, Interval, and Handling Capacity using the baseline method. Distinguish clearly between collective vs selective operation and Phase I vs Phase II fire service operation.

B. Escalators & Travelators

• Escalator: Inclined, continuous moving staircase. Used for high traffic (malls, metro).

  • Components: Drive unit, truss, steps, handrail, comb plates, safety devices (step gap, brush, skirt).

• Travelator/Moving Walkway: Horizontal or slight incline. Used for long distances (airports).

• Key Difference from Lifts: Continuous movement, no waiting, higher throughput for short vertical distances, no cabin enclosure.

C. Car Parking Systems

• Surface Parking: Simple, land-intensive. Stall size: ~2.5m x 5.5m (incl. aisle).

• Multi-Storey: Ramps or lifts. 90° parking (most efficient) vs. 45°/60°.

• Automated: Mechanical/pallet systems (stacked, rotary, shuttle). Saves space, higher cost.

• Layout Planning: Consider turning radius, circulation, entry/exit, pedestrian safety.

II. FIRE SAFETY & PROTECTION SYSTEMS

A. Fundamental Concepts

• Classification of Fire (IS/NFPA):

  • Class A: Ordinary combustibles (wood, paper).

  • Class B: Flammable liquids/gases (petrol, LPG).

  • Class C: Energized electrical equipment.

  • Class D: Combustible metals (sodium, magnesium).

  • Class E: (Older) Electrical fires (now often Class C).

  • Class F/K: Cooking oils/fats (deep fryers).

• Modes of Fire Spread:

  • Conduction: Through solids (steel, concrete).

  • Convection: Through fluids (air, smoke).

  • Radiation: Heat waves (primary mode across gaps).

B. Active Fire Protection Systems

1. Fire Hydrant System

• Components: Water source (tank/reservoir), pumps (jockey + main), piping (ring main), hydrant valves, hoses, nozzles.

• Requirements: NBC Part 4 specifies coverage area, pressure (≥4 kg/cm²), flow rate. Two independent sources mandatory for high-rises.

2. Automatic Sprinkler System

• Types:

  • Wet Pipe: Most common; pipes always charged with water.

  • Dry Pipe: Pipes filled with air/ nitrogen; for freezing areas.

  • Deluge: All nozzles open; triggered by fire detection; for high hazard.

  • Pre-action: Hybrid (dry pipe + detection); for sensitive areas (data centers).

• Design: Based on design area & density (liters/min/m²) per IS 15185/NBC.

3. Carbon Dioxide (CO2) System

• Storage: High-pressure cylinders (liquid CO2) or low-pressure banks.

• Discharge: Total flooding (enclosed volume) or local application.

• Use: Electrical rooms, transformer vaults, archives. Hazard: Asphyxiation; requires safety interlocks.

4. Fire Alarm & Detection

• Types: Heat detectors (rate-of-rise, fixed temp), smoke detectors (ionization, photoelectric), flame detectors.

• System: Addressable/ conventional panels, manual call points, sounders/strobes.

5. Other Systems

• Foam: For Class B fires (petrol, oil). AFFF (Aqueous Film Forming Foam).

• Dry Chemical: Monoammonium phosphate (ABC powder) for multi-class.

C. Passive Fire Protection & Building Layout

1. NBC Provisions (Part 4)

• Building Classification: Groups A (residential) to G (industrial).

• Compartmentalization: Divide building into fire compartments with fire-resistant (FR) construction (walls/doors/floors). FR rating in hours (e.g., 2h, 4h).

• Fire Doors: Self-closing, intumescent seals, FR rated. Must be kept closed.

2. Fire Escapes & Escape Routes

• Requirements: Number/width based on occupant load. Two remote, enclosed stairs for high-rises.

• Travel Distance: Max distance to an exit (varies by occupancy).

• Service Duct Escape: Ducts for services (pipes, ducts) must not compromise fire integrity. Fire dampers required at fire-rated walls.

3. High-Rise Specific (NBC)

• Fire Lift: Dedicated, 2-hour FR shaft, separate lobby.

• Control Room: With fire alarm panel, communication.

• Pressurization: Staircases & lift lobbies.

• Wet Riser/Downcomer: Internal hydrant system with vertical pipes.

D. Administrative & Planning Aspects

• Supervisor's Role: Ensure compliance during construction, conduct fire drills, maintain systems, train staff.

• Planning-Stage Integration: Early coordination of fire strategies (egress, compartmentation, detection) with architectural design.

[!TIP] Exam Focus: Memorize fire classes with examples. Know NBC requirements for high-rises (fire lift, pressurization, two stairs). Understand difference between wet/dry/pre-action sprinklers. Fire dampers in service ducts are critical.

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

A. Ventilation Systems

• Objectives: Dilute/remove indoor pollutants (CO2, odors, moisture), provide fresh air, control temperature/humidity.

• Types:

  • Natural: Wind-driven, buoyancy (stack effect). Low cost, climate-dependent.

  • Mechanical:

    • Exhaust: Removes stale air; creates negative pressure.

    • Supply: Forced fresh air; creates positive pressure.

    • Balanced: Equal supply & exhaust; pressure neutral.

B. Air Conditioning Systems

1. Unitary vs Central

2. Types of Central AC Systems

• All-Air: Conditioned air distributed via ducts (e.g., CAHV). No water in occupied space.

• All-Water: Conditioned water to fan coil units (FCUs) in rooms. No air ducts.

• Air-Water: Conditioned air from central AHU + conditioned water to FCUs.

• Refrigerant-Based (VRF/VRV): Variable refrigerant flow; multiple indoor units on one outdoor system.

3. Essentials of AC System

• Refrigeration Cycle: Compressor → Condenser → Expansion valve → Evaporator.

• Air Distribution: Supply/return grilles, ducts, diffusers, balancing dampers.

C. Thermal Insulation

• Purpose: Reduce heat gain (summer) / heat loss (winter).

• Building Envelope:

  • Walls: Cavity wall insulation, external/internal plaster, insulating blocks, cladding.

  • Roof: False ceiling with insulation, terrace garden, reflective paint.

• Materials: Expanded polystyrene (EPS), extruded polystyrene (XPS), mineral wool, glass wool, polyurethane foam.

• Thermal Comfort (ASHRAE 55): Depends on air temp, mean radiant temp, humidity, air velocity, clothing, metabolic rate.

D. Environmental Systems for Specific Buildings

• Swimming Pools:

  • Ventilation: High air changes (6-12 ACH) to remove chloramines (DBPs).

  • DBP Mitigation: Use UV systems or Ozonation to break down chloramines (trichloramines cause "pool smell" & irritation).

  • Algae Control: Filtration (sand/diatomaceous earth), chlorination (continuous + shock), algaecides (copper/silver), water circulation.

• Open-Air Theatres:

  • Acoustic Design: Shell/reflectors for sound projection, audience area absorption.

  • Ventilation: Natural ventilation (orientation, wind catchers) or mechanical for enclosed sections.

[!TIP] Exam Focus: Differentiate unitary vs central AC clearly. Know DBP mitigation methods (UV/Ozone) for pools. Understand thermal comfort parameters. Sketch the basic refrigeration cycle.

IV. ACOUSTICS & NOISE CONTROL

A. Fundamentals of Architectural Acoustics

1. Reverberation Time (RT)

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

• Sabine's Formula: RT₆₀ = 0.161 V / A

  • V = Volume of room (m³)

  • A = Total absorption (sabins) = Σ(Sᵢ × αᵢ) where Sᵢ = area of surface i, αᵢ = absorption coefficient.

• Factors Affecting RT: Room volume, surface materials (absorption), furnishings/audience.

2. Sound Absorption

• Materials: Porous (fiberglass, foam, fabric), resonant (perforated panels), membrane.

• Good Acoustics: Requires optimum RT (e.g., 0.8-1.2s for speech, 1.5-2.0s for music).

3. Acoustic Design of Auditoriums

• Shape: Shoebox (orchestra halls) vs. arena (theatres). Avoid parallel walls, concave surfaces (focusing).

• Materials: Reflective surfaces (concrete, wood) for early reflections; absorptive (curtains, seats) for RT control.

• Audience Absorption: Significant; accounted for in design calculations.

• Other: Balcony geometry, canopy/reflectors, diffusers.

B. Noise Control

1. Sources of Noise in Buildings

• External: Traffic, aircraft, industry.

• Internal: People, equipment (HVAC, plumbing, lifts).

• Service Equipment: Chillers, pumps, fans, ducts.

2. Planning Stage Control

• Site Layout: Place noise-sensitive areas (bedrooms) away from noise sources.

• Building Orientation: Shield facades with service cores, non-sensitive rooms.

• Shape: Avoid sound focusing.

3. Sound Insulation of Building Elements

• Walls/Floors: Mass (heavy materials), damping, decoupling (double wall, staggered studs).

• Windows: Double/triple glazing, thick glass, air gap, acoustic seals.

• STC (Sound Transmission Class): Single-number rating of assembly's airborne sound insulation.

4. Noise Rating (NR) Curves

• Definition: Curves defining acceptable indoor noise levels (dB) vs. octave band center frequency.

• Use: Specify maximum permissible noise from HVAC systems. Lower NR = quieter (e.g., NR-25 for libraries, NR-40 for offices).

[!TIP] Exam Focus: Sabine's formula is MUST. Know typical RT values for different rooms. STC vs NR – STC for partitions, NR for background noise. Sketch auditorium acoustic features (reflectors, absorbers).

V. WATER SUPPLY, DRAINAGE & SANITATION SYSTEMS

A. Water Supply Systems for Multi-Storeyed Buildings

• Direct System: Mains pressure feeds all floors directly. Requires high municipal pressure (>2.5 kg/cm²).

• Indirect System: Underground tank → pumps → overhead tank → gravity feed. Most common.

• Pressure Boosting: For high-rises where overhead tank not feasible. Uses hydro-pneumatic systems or variable speed pumps with pressure sensors on each floor/zone.

• Pipes & Materials:

  • GI (Galvanized Iron): Traditional, being phased out.

  • CPVC: Chlorinated PVC; for hot/cold, rigid.

  • HDPE: Flexible, jointless, for underground/main lines.

  • PEX: Cross-linked polyethylene; flexible, for internal.

  • Stainless Steel: Premium, durable.

Water Supply Fixtures & Appliances: Taps (compression, quarter-turn), valves (gate, ball, PRV), showers, faucets, WC cisterns, urinals.

B. Swimming Pool Engineering

• Water Treatment Process:

  1. Filtration: Sand filter (most common) or D.E. filter. Removes suspended solids.

  2. Disinfection: Chlorination (sodium hypochlorite, chlorine gas) to kill pathogens. Maintain free chlorine residual 1-3 ppm.

  3. pH Control: Maintain 7.2-7.8 (soda ash/acid).

• DBP Mitigation: As above (UV/Ozone).

• Algae Control: Maintain chlorine residual, copper-silver ionization, algaecides, good circulation/filtration.

C. General Plumbing & Piping

• Piping Layout Principles: Shortest route, avoid sharp bends, adequate slope for drainage, accessibility for maintenance, separation from electrical/structural.

• Refuse (Waste) Collection: One-pipe system (all wastes to single stack) vs. two-pipe (separate soil & waste). Traps & vents prevent siphonage and allow air flow.

VI. SUSTAINABILITY & GREEN BUILDING CONCERNS

A. Green Building Principles

• Core Concerns: Energy efficiency, water conservation, material/resource efficiency, indoor environmental quality, site sustainability.

• Rating Systems (India):

  • LEED (USGBC): Points-based; categories: Sustainable Sites, Water Efficiency, Energy, Materials, IEQ, Innovation.

  • GRIHA (ADaRSH): 4-star max; holistic, lifecycle approach.

  • IGBC (CII): Tailored for Indian context.

• Key Strategies: Solar passive design, rainwater harvesting, sewage treatment, low-VOC materials, daylighting, efficient HVAC.

B. Rainwater Harvesting (RWH)

• Methods: Rooftop (catchment), surface runoff (catchment).

• Components:

  1. Catchment (roof/ground).

  2. Conveyance (gutters, downpipes).

  3. Screening (first flush, filters).

  4. Storage (tank, underground/sump).

  5. Distribution (pump to fixtures/landscaping).

• Design: Calculate rainfall yield = Catchment area × rainfall × runoff coefficient.

• Integration: Connect storage to non-potable uses (flushing, gardening).

VII. LANDSCAPING, HORTICULTURE & EXTERNAL SERVICES

A. Landscaping & Horticulture

• Objectives: Aesthetics, microclimate control (shade, windbreak), air purification, erosion control, psychological well-being.

• Plant Selection: Native/drought-tolerant, low maintenance, non-invasive roots, appropriate scale.

• Irrigation: Drip/sprinkler systems; use treated wastewater or RWH water.

B. Building Exterior & Site Services

• Integration: Route external services (water, drainage, electrical) away from tree roots, coordinate with landscape zones.

• External Lighting: Pathway, security, feature lighting. Use LEDs, motion sensors, dark-sky compliant fixtures to reduce light pollution.

VIII. BUILDING CODES, STANDARDS & ADMINISTRATION

A. National Building Code (NBC) of India

• Building Classification (Occupancy Groups):

  • Group A: Residential.

  • Group B: Educational.

  • Group C: Institutional (hospitals, jails).

  • Group D: Assembly (theatres, stadiums).

  • Group E: Business (offices).

  • Group F: Mercantile (shops).

  • Group G: Industrial.

  • Group H: Storage.

  • Group J: Hazardous.

• Relevance to Services: Dictates minimum requirements for fire safety, plumbing fixtures, accessibility, structural safety based on occupancy and height/area.

B. Administrative & Supervisory Functions

• Functions: Planning & coordination of MEP services, quality control, schedule monitoring, budget management, vendor/client coordination, ensuring code compliance, safety supervision, documentation/as-built drawings.

• Coordination (MEP): Clash detection (using BIM), spatial coordination in shafts/risers, sequencing of installation.

IX. BUILDING SECURITY & ACCESS CONTROL

A. Access Control Systems

• Integration: Often linked with CCTV, alarm systems, time-attendance.

[!TIP] Exam Focus: NBC Groups must be memorized. Supervisor's functions are about coordination & compliance. For access control, know one key feature and application of each type.