RIBA Architecture Parts 1, 2 and 3 Environmental Design and Building Services Syllabus

Environmental Design and Building Services syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Environmental Design and Building Services in RIBA Architecture Parts 1, 2 and 3, not a summary of it.

1. 1

   Climate, Comfort and Passive Design

   5 topics

   • Thermal comfort and human physiology
     • PMV, PPD and adaptive comfort
     • Overheating risk and TM59 assessment
   • Solar geometry and shading
     • Sun path, azimuth and altitude
     • Passive solar gain and brise-soleil
   • Natural ventilation strategies
     • Stack, cross and single-sided ventilation
   • Daylighting and glare control
   • Thermal mass and the building fabric
2. 2

   Energy and Low-Carbon Strategy

   5 topics

   • Fabric-first and the energy hierarchy
   • Passivhaus principles and certification
   • Renewable technologies
     • PV, solar thermal and heat pumps
     • Heat networks and district energy
   • Operational versus embodied carbon
   • Net-zero pathways and the RIBA 2030 Challenge
3. 3

   Building Services Integration

   5 topics

   • Heating, ventilation and air conditioning
     • MVHR and ductwork strategy
   • Water supply, drainage and SuDS
   • Electrical, lighting and power distribution
   • Vertical transportation and lifts
   • Coordination of services with structure and fabric
4. 4

   Environmental Assessment and Compliance

   4 topics

   • BREEAM and assessment methodologies
   • SAP, SBEM and energy modelling
   • Part L and conservation of fuel and power
   • Post-occupancy evaluation and the performance gap

Environmental Design and Building Services flashcards for RIBA Architecture Parts 1, 2 and 3

20 of 57 cards from the Environmental Design and Building Services deck — real questions with worked answers.

1. In thermal comfort theory, what are the six primary factors governing human thermal comfort?

   Four environmental factors — air temperature, mean radiant temperature, air velocity, and relative humidity — plus two personal factors: metabolic rate (activity, in met) and clothing insulation (in clo).

2. What does Fanger's PMV/PPD model predict, and what PPD value corresponds to optimal (PMV = 0) conditions?

   The Predicted Mean Vote (PMV) rates thermal sensation on a 7-point scale ($-3$ cold to $+3$ hot); Predicted Percentage Dissatisfied (PPD) gives the percentage of occupants dissatisfied. Even at neutral PMV $= 0$, PPD has a minimum of about $5\%$ — comfort can never satisfy everyone.

3. Define the 'dry resultant temperature' (operative temperature) and give its common approximation for still-air indoor conditions.

   Operative temperature is the weighted average of air temperature ($t_a$) and mean radiant temperature ($t_r$) experienced by an occupant. For low air speeds it is approximated as $t_{op} = \frac{t_a + t_r}{2}$.

4. What is the principle behind the adaptive thermal comfort model used for naturally ventilated buildings?

   Occupants of free-running buildings adapt their comfort expectations to recent outdoor conditions, so the neutral indoor temperature rises with the running mean outdoor temperature. It allows a wider, sliding comfort band rather than a fixed setpoint (BS EN 16798 / ASHRAE 55 adaptive method).

5. Define solar altitude and solar azimuth angles.

   Solar altitude is the vertical angle of the sun above the horizon; solar azimuth is the horizontal angle of the sun's position measured from due south (or north). Together they fix the sun's position in the sky for shading design.

6. Why are horizontal shading devices (overhangs) most effective on south-facing facades in the UK, while east/west facades need vertical fins or screens?

   At solar noon the south sun is high in altitude, so a horizontal overhang easily blocks it. East and west sun is low on the horizon in morning/evening, so it slips under overhangs; vertical fins, louvres or movable screens are needed to block low-angle direct gain.

7. What is a solar shading mask (sun-path / stereographic diagram), and what is it used for?

   A sun-path diagram plots solar altitude and azimuth across the year; overlaying a shading mask (the portion of sky a device blocks) lets designers determine exactly when a window is shaded or exposed, sizing overhangs and fins for each orientation.

8. State the cut-off (shadow) angle relationship used to size a simple horizontal overhang of depth $d$ for a window of height $h$ below it.

   The overhang fully shades the window when the solar altitude exceeds the profile angle $\alpha$, where $\tan\alpha = \frac{h}{d}$, so the required depth is $d = \frac{h}{\tan\alpha}$.

9. Distinguish the three main natural ventilation strategies: single-sided, cross, and stack ventilation.

   Single-sided uses openings on one facade (effective depth roughly up to $2\times$ floor-to-ceiling height). Cross ventilation uses openings on opposite facades driven by wind pressure (up to about $5\times$ height). Stack ventilation uses buoyancy — warm air rising and exiting high openings, drawing cool air in low.

10. What physical principle drives stack (buoyancy) ventilation, and how does the driving pressure depend on height and temperature?

    It is driven by the density difference between warm indoor and cool outdoor air. The stack pressure is $\Delta p = \rho g h \frac{\Delta T}{T}$, so greater height ($h$) between inlet and outlet and larger temperature difference ($\Delta T$) increase airflow.

11. What is night purge (night-time cooling) ventilation and which building characteristic makes it effective?

    Night purge ventilates the building with cool night air to flush out heat stored during the day, pre-cooling the structure for the next day. It relies on exposed thermal mass to absorb daytime heat and release it overnight.

12. Define the daylight factor and state typical recommended average values for a habitable room.

    The daylight factor is the ratio of internal illuminance at a point to simultaneous unobstructed external horizontal illuminance under a CIE overcast sky, expressed as a percentage: $DF = \frac{E_{in}}{E_{out}} \times 100\%$. Around $2\%$ average is adequate for general spaces and $5\%$ for well-daylit rooms.

13. Name the three components that make up the daylight factor.

    The Sky Component (direct light from the sky), the Externally Reflected Component (light reflected from external surfaces/buildings), and the Internally Reflected Component (light reflected off internal surfaces): $DF = SC + ERC + IRC$.

14. What are the climate-based daylight metrics that have largely replaced the static daylight factor, and what does each measure?

    Spatial Daylight Autonomy (sDA) — percentage of floor area meeting a target illuminance (e.g. 300 lux) for a set percentage of occupied hours; and Annual Sunlight Exposure (ASE) — percentage of area receiving excessive direct sun, used to flag glare/overheating risk.

15. What is Daylight Glare Probability (DGP) and what causes discomfort glare from daylight?

    DGP predicts the fraction of occupants likely to be disturbed by glare, based on the luminance and solid angle of bright sources (e.g. sky/sun seen through windows) relative to the adapted background. High contrast between a bright source and darker surroundings causes discomfort glare; controlled by shading, light shelves and surface reflectances.

16. Define thermal mass and the property 'admittance' used to quantify a material's dynamic thermal response.

    Thermal mass is a material's ability to absorb, store and release heat. Admittance ($Y$, $\mathrm{W/m^2K}$) measures the rate at which a surface exchanges heat with the space over a daily cycle in response to a $1\,\mathrm{K}$ swing — high-admittance (heavy) surfaces dampen internal temperature swings.

17. What is the decrement factor and time lag of a building element, and why do they matter for heavyweight construction?

    Decrement factor is the ratio of cyclic heat flow through an element to the steady-state flow (how much the external temperature swing is damped). Time lag is the delay between peak external and peak internal temperature. Heavy walls give low decrement factor and long time lag, smoothing and delaying heat to reduce peak overheating.

18. Explain how thermal mass combined with night ventilation reduces summer overheating in a building.

    Exposed mass absorbs internal heat gains during the day, keeping daytime temperatures lower; at night, ventilation removes that stored heat from the mass, recharging its cooling capacity for the following day — a 'fabric battery' effect.

19. State the 'fabric-first' approach and the energy hierarchy it sits within.

    Fabric-first means minimising energy demand by optimising the building fabric (insulation, airtightness, thermal bridging, glazing, form) before adding services or renewables. The energy hierarchy is: 1) reduce demand (be lean), 2) supply efficiently (be clean), 3) use renewables (be green).

20. Why does the energy hierarchy prioritise demand reduction over renewable generation?

    Reducing demand is permanent, maintenance-free and avoids the cost, embodied carbon and degradation of equipment. Renewables and efficient supply only address the energy that remains, so over-sizing systems to compensate for a poor fabric is costlier and less robust over the building's life.

See more Environmental Design and Building Services flashcards →

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