1 of 34

Construction Technology

Dr Adewale Abimbola, FHEA, GMICE

www.edulibrary.co.uk

2 of 34

Aim and Objectives

Aim: Primary Services: Electricity, Ventilation, Heating, and Air-conditioning.

Objectives: At the end of the lesson, the students should be able to:

Describe the supply arrangements for primary services.

Explain the distribution arrangements for primary services.

3 of 34

Learning Outcomes and Assessment Criteria

P7. Describe the supply arrangements for primary services.

P8. Explain the distribution arrangements for primary services

4 of 34

INTRODUCTION

¢ Utility services are essential systems that supply energy, water, and communications to buildings and communities.

¢ Efficient provision and management of utilities is vital for safety, economic development, and quality of life (London.gov.uk, 2020).

Types of Utility Services

    • Water Supply: Provides potable water for domestic and commercial usage.
    • Electricity: Supplies power for lighting, appliances, and machinery.
    • Gas: Used for heating, cooking, and some industrial applications.
    • Telecommunications: Includes broadband, telephone, and data networks.
    • Others: District heating, drainage, and waste management (alsyedconstruction.com, 2024; Gov.uk, 2025).

5 of 34

Electricity

5

6 of 34

Primary Services - Electricity

Electricity supplies

  • Electricity is generated at power stations and fed to the national grid system from substations, after the voltage has been increased by transformers from 11 – 25kV to 400kV, 275kV, & 132kV.
  • Electricity is carried out to grid supply points by transmission lines using overhead and underground cables
  • At grid substations, transformers reduce the voltage and bulk supplies of electricity are feed to regional distribution networks at 33/11 kV.
  • Distribution network operators carry electricity along local overhead lines and underground cables to streets and neighbourhoods.
  • Further small transformers on poles or in street cabinets reduce voltage again (typically to 230/400 V).
  • At the final transformer, electricity at 230 V single‑phase (or 400 V three‑phase, four wire supply, for some users) enters homes and businesses through service cables and meter tails.

Figure 1. Electricity generation and distribution.

7 of 34

Primary Services - Electricity

Distribution of Electricity in the Building

  • The electrical supply to a domestic installation is 230 volt single phase and is designed with the following safety objectives:
  • Proper circuit protection to earth to avoid shocks to occupant (protective bonding).
  • Prevention of current leakage.
  • Prevention of outbreak of fire.

Figure 2. Typical electrical supply intake details (Chudley and Greeno, 2016).

Difference between single and three phase electricity: https://www.youtube.com/watch?v=JYjgjPCYr_U

8 of 34

Primary Services - Electricity

Distribution of Electricity in the Building

  • Distribution of electricity in domestic properties is normally in the form of circuits which serve power and lighting requirements.
  • Figure 3 shows typical fuse ratings and applications.
  • Consumer’s power supply control unit, conveniently abbreviated to ‘consumer unit’, contains the main double pole isolating switch controlling the Line (Live) and Neutral conductors, called bus bars. These connect to the circuit protection devices for individual circuits.
  • It also contains the earth bar, plus a range of individual circuit overload safety protection devices. Overload protection is provided by miniature circuit breakers attached to the live or phase bar.

Figure 3. Typical meter box and consumer unit layout (Chudley and Greeno, 2016).

9 of 34

Primary Services - Electricity

Distribution of Electricity in the Building

  • Additional protection is provided by a split load residual current device (RCD) dedicated specifically to any circuits that could be used as a supply to equipment outdoors, e.g. power sockets on a ground floor ring final circuit.
  • RCD - a type of electromagnetic switch or solenoid which disconnects the electricity supply when a surge of current or earth fault occurs.
  • Note that with an overhead supply, the MAIN SWITCH is combined with a 100 mA RCD protecting all circuits.
  • Over‑current devices (MCBs/fuses) are sized so that if too much current flows (overload or fault), they trip before cables or equipment overheat.
  • Circuits (1) to fixtures, i.e. lights, cooker, immersion heater and smoke alarms.
  • Circuits (2) to socket outlets that could supply portable equipment outdoors.

Figure 4. Typical split load consumer unit (Chudley and Greeno, 2016).

10 of 34

11 of 34

Self-Assessment Task

1) Describe the supply arrangement for the primary service of electricity.

​

Hint: references to

- The description must include supply from the mains/sources to the boundary of the property. Also, include description of the difference between single-phase and three-phase electricity.

2) Explain the distribution arrangements for the primary service of electricity.

Hint: references to

- The explanation must include distribution of the primary service within a property.

Note:

  • Use annotated illustrations to support your description.
  • Ensure you provide the sources of the information.

12 of 34

Ventilation

12

13 of 34

Natural Ventilation

Figure 5. Wind-driven ventilation (Regel-air, 2021)

  • Natural ventilation relies on wind and buoyancy (stack effect) rather than fans, using openings, vents and architectural form to drive airflow through buildings (CIBSE, 2015).
  • Wind‑driven ventilation uses external wind pressure differences around the building envelope, with inlets and outlets positioned to capture prevailing winds and exhaust stale air, often assisted by roof cowls or ventilators (Awbi, 2017).
  • Cross ventilation occurs when air flows from one side of a space to the other through openings on opposite facades, and is particularly effective in shallow‑plan buildings where through‑flow can be maintained (CIBSE, 2015).

Figure 6. Cross ventilation (Architropics, 2022)

14 of 34

Natural Ventilation

  • Stack ventilation uses temperature differences between indoor and outdoor air to create vertical air movement, typically via chimneys, high‑level openings or atria, can be effective in multi‑storey circulation spaces (CIBSE, 2015).
  • Natural strategies can reduce energy use and plant costs but require early‑stage design integration, careful control of noise, draughts and security, and may need mixed‑mode systems where mechanical assistance is provided in extreme conditions (CIBSE, 2010; Awbi, 2017).
  • On construction projects, achieving the intended natural ventilation performance depends on correct installation of openings, controllable vents and shading devices, as well as commissioning and user training (CIBSE, 2015).

Figure 7. Stack ventilation (MBS Architecture, 2024).

15 of 34

Mechanical Ventilation

  • Supply and extract fans can be arranged as balanced systems, providing controlled fresh air and removing stale air, which is important in deep‑plan offices, healthcare facilities and high‑occupancy spaces (Awbi, 2017).

How does the Pressure Differential System protect exit routes from smoke? Step-by-step activation

ELTATRADE Rapid Response Exhaust Fan Demo

  • Pressure differential systems create positive or negative pressure zones (for example, pressurised stairwells or isolation rooms) to prevent smoke spread or contamination, and must be carefully commissioned to meet design pressure differentials (CIBSE, 2010).
  • Mechanical ventilation uses powered equipment such as fans and duct systems to move air into and out of buildings, helping to control indoor air quality, temperature and humidity where natural forces are insufficient (CIBSE, 2015).

16 of 34

Mechanical Ventilation

Construction waste vacuum cleaner

  • Local exhaust systems, such as fume cupboards, dust extraction or kitchen canopies, remove pollutants at source and are widely used on construction projects to control dust, fumes and odours (HSE, 2020).
  • Vacuum and extraction systems can also be installed on sites for task‑based controls (e.g. on-tool extraction for cutting concrete), reducing worker exposure to respirable dust and complying with health and safety regulations (HSE, 2020).
  • For construction managers, mechanical ventilation requires coordination of plant rooms, risers, duct routes, acoustic treatment and fire dampers, and must align with Building Regulations and relevant standards (CIBSE, 2015).

Local Exhaust Ventilation (LEV) - ESTA DUSTOMAT 4 Series UK

17 of 34

Heating

17

18 of 34

Heat Generator

  • Heat generators are the components that convert fuel or electricity into useful heat for buildings, and must be selected to match the load profile, building type and energy strategy (CIBSE, 2015).
  • Gas boilers remain common in many existing non‑domestic and residential schemes, using burners and heat exchangers to transfer combustion heat into water for distribution (Chartered Institute of Building, 2014).

Condensing Boilers

19 of 34

Heat Generator

  • Solid fuel appliances (e.g. biomass boilers, log or pellet burners) can support decarbonisation strategies where sustainable fuel supply chains exist, but require more space for fuel storage, handling and ash removal (CIBSE, 2019).

Biomass Boilers - How it Works

20 of 34

What Is a Biomass Boiler? Happy Energy CEO explains

21 of 34

Heat Generator

  • Combined heat and power (CHP) plant simultaneously produces electricity and useful heat from a single fuel input.
    • Fuel (usually gas/diesel) is burned in the engine or turbine.
    • The engine spins a generator to produce electricity.
    • Engine cooling water and exhaust gases become very hot.
    • Heat exchangers capture waste heat from cooling water and exhaust.
    • Heat warms water in the heat recovery system for heating/hot water.
    • Electricity powers equipment; hot water heats the building.
    • Controls adjust engine speed to match electricity and heat demand.
  • In construction planning, coordination with structural, acoustic and fire design is essential for plant rooms housing boilers, CHP or solid fuel units, including flues, ventilation and access for maintenance (CIBSE, 2015).

CHP | Combined Heat and Power

22 of 34

Heating Distribution

  • Heating distribution systems move heat from the generator to the occupied spaces and are a major influence on efficiency, controllability and installation cost (CIBSE, 2015).

How Does Hot Water Recirculation Work?

How A Gas Furnace Works (Animated Schematic) - YouTube

  • Hot water (wet) systems circulate heated water through pipework to emitters such as radiators, convectors or fan coil units, and are widely used in UK residential and commercial buildings (CIBSE, 2015).
  • Forced‑air systems distribute heated air via ductwork, often combining heating, ventilation and sometimes cooling, which can simplify plant but requires careful duct routing and noise control (CIBSE, 2016a).

23 of 34

Heating Distribution

  • Steam distribution is mainly found in industrial, hospital or legacy systems where high‑temperature heat is required, and it demands robust pipework, condensate management and strict safety controls (CIBSE, 2015).
  • Good distribution design minimises heat losses (e.g. insulation on pipework and ducts), avoids excessive pumping or fan energy, and allows zoning so that different parts of a building can be controlled separately (Chartered Institute of Building, 2014).

Steam Heating Systems Basics hvacr

24 of 34

Heating Delivery to Spaces

  • Heat delivery refers to the terminal units that transfer heat from the distribution system into the room air or building fabric, directly affecting thermal comfort and user experience (CIBSE, 2015).
  • Radiators transfer heat mainly by radiation from hot water to the surrounding air; they are simple, robust and common in residential and small commercial projects (CIBSE, 2015).
  • Fan coil units use a small fan to blow air over a hot (and often chilled) water coil, giving rapid response and local control, and are frequently used in offices, hotels and mixed‑use developments (CIBSE, 2016a).

Fan Coils 101: How Fan Coil Units Work

25 of 34

Heating Delivery to Spaces

  • Air handling units (AHUs) condition and distribute air centrally, often in conjunction with variable air volume or constant volume duct systems, enabling combined control of temperature, ventilation and filtration (CIBSE, 2016a).
  • For construction managers, coordination of emitters and ductwork with architecture and services (e.g. ceiling heights, coordination zones, access panels) is critical to avoid clashes and rework on site (Chartered Institute of Building, 2014).

Air Handling Unit Working principle | HVAC 08

26 of 34

Air Conditioning

26

27 of 34

Split Air Conditioning Systems

How a Split Air‑conditioning (AC) Unit Works.

  • The indoor fan pulls warm room air through the filter and across the cold evaporator coil.
  • The refrigerant in the evaporator coil absorbs heat, and the fan blows the cooled air back into the room.
  • Warm refrigerant gas flows through the refrigerant pipes to the outdoor unit.
  • The outdoor compressor squeezes the refrigerant, raising its pressure and temperature.
  • Hot refrigerant passes through the outdoor condenser coil, where the outdoor fan blows air over it to dump heat outside.
  • The cooled liquid refrigerant goes through the expansion valve, dropping in pressure and temperature before returning to the indoor coil.
  • The thermostat and control system switch the compressor and fans on and off to maintain the set room temperature.

Summary: Indoor unit takes heat from the room → refrigerant carries heat outside → outdoor unit dumps heat into the outdoor air → cooled refrigerant returns inside to repeat the cycle.

Figure 8. How an air conditioner works. (Ali, 2025).

28 of 34

Split Air Conditioning Systems

Split systems

  • Split systems consist of separate indoor evaporator and outdoor condenser units connected by refrigerant pipework, serving individual rooms or zones without ductwork (CIBSE, 2015).
  • They provide flexible, zoned cooling for smaller projects, retrofits or spaces where ducting is impractical, with lower upfront costs but potentially higher running costs per unit (Awbi, 2017).
  • Popular in residential extensions, small commercial units and hotels; easier site coordination but requires external wall space and noise mitigation near bedrooms (Chartered Institute of Building, 2014).

Split Air Conditioning System | How HVAC Split System Air Conditioners Work

29 of 34

Central Air Conditioning

Central air conditioning

  • Central systems use a single large chiller or air handling unit serving multiple zones via extensive ductwork, providing uniform conditioning across large commercial or multi-residential buildings (CIBSE, 2015).
  • They offer high efficiency for steady loads and enable central control of temperature, humidity and filtration, but require significant plant room space, duct risers and distribution losses (Awbi, 2017).
  • Common in offices, hospitals and universities where consistent indoor conditions are needed; construction managers must coordinate ductwork with structure, ceilings and fire compartmentation (CIBSE, 2015).

How Air Conditioning Works

30 of 34

Primary Services – Air Conditioning Ductwork

  • Ducted air-conditioning is the most efficient air-conditioning systems. It is useful in homes, offices, business houses and industrial premises.
  • Using one system, you can keep different temperature levels in various areas of the building (Fig. 9). E.g., the bedroom temperature can be set cooler or warmer than the living room, etc.
  • The ducted air-conditioning system is ideal for big houses with more than three bedroom. It can be combined with a dehumidifier system to reduce the amount of moisture and give maximum comfort.

Air Conditioning Ductwork – How it works?

  • A ducted air-conditioning system funnels cool air from a central unit. A series of ducts flows the air to every room.
  • You can control the airflow by dividing the area into zones as per your need. Thus, you can keep the house warm in winters and cool in summers.

Figure 9. Ducted Split Systems Air-conditioners.

31 of 34

Central Air Conditioning & Split systems

Key Components of Air Conditioning Systems

    • Evaporator: Absorbs heat from indoor air as refrigerant evaporates inside the coil, cooling the air before it returns to the space; located in fan coil units, cassettes or AHUs (Awbi, 2017).
    • Compressor: Compresses low-pressure gas to high-pressure gas and driving the refrigeration cycle. It circulates refrigerant between evaporator and condenser, (CIBSE, 2015).
    • Condenser: Releases heat from high-pressure refrigerant gas to outdoor air or water; air-cooled in split systems, water-cooled in central chillers (CIBSE, 2015).
    • Expansion valve: Regulates refrigerant flow into the evaporator, controlling cooling capacity and maintaining efficient operation across varying loads (CIBSE, 2015).
    • Cassette units: Ceiling-mounted evaporators with four-way air distribution (Fig. 10), blending with suspended ceilings and providing even coverage in open-plan offices (CIBSE, 2016b).
  • Central systems demand early coordination of plant rooms, risers and bulkheads; split systems need outdoor unit fixings, drainage and screening from view (Chartered Institute of Building, 2014).
  • Both require condensate drainage, electrical supplies, access for maintenance and refrigerant handling by F-Gas qualified engineers during commissioning (CIBSE, 2015).

Figure 10. Cassette air conditioning units.

Figure 11. Air-conditioning ductwork.

32 of 34

Primary Services – Air Conditioning Inspections & Legislation

The Energy Performance of Building Directive (EPBD) 2002 is a EU Directive 2002/91/EC aimed to cut building carbon emissions through efficiency standards; transposed into UK law.

This directive was implemented into UK legislation in the form of the Energy Performance of Buildings Regulations (EPBR) 2012, which requires energy certificates and AC inspections for non-domestic buildings.

New air conditioning systems over 12 kW installed after January 2008 must be inspected within 5 years of installation.

From 4th January 2011, it was made a legal requirement for any buildings with over 12kW of total cooling to have a TM44 Air Conditioning Inspection Survey and Report carried out by an Accredited Air Conditioning Inspector and for this report to be lodged with the government’s Non-Domestic Energy Performance Certificate Register (Aura, 2022).

Practical threshold: >1,000 sq ft (~93m²) air-conditioned space typically exceeds 12kW threshold, triggering mandatory TM44 survey.

Building Regulations Part F (ventilation) and Part L (conservation of fuel/energy) set minimum efficiencies and commissioning standards for all AC installations (HM Government, 2021).

33 of 34

Self-Assessment Task

 Explain the distribution arrangements for ONE of the two primary services:

1) Heat generators (at least ONE. E.g., boilers, solid fuel burners, & combined heat and

power plant), heating distribution (at least ONE. E.g., hot water, forced air, & steam) and heat delivery (at least ONE. E.g., radiators, fan coil units, & air handling units).

2) Ventilation (mechanical [(at least ONE. E.g., fans, pressure systems, vacuum systems, & exhaust systems)] and natural [(at least ONE. E.g., wind driven, stack ventilation, & cross ventilation)]), and air conditioning ductwork (Central air vs split system air conditioning).

Note:

  • Use annotated illustration to support your description.
  • Ensure you provide the sources of the information.

34 of 34

References/Bibliography