Architectural Specification for Healthy Buildings
The specification, especially when started early in the concept design stage, can be a powerful tool to capture, coordinate and realise a collective, multidisciplinary vision for a healthy building.
Architectural specifications are legal instruments, technical manifestos and quality control frameworks rolled into one. Specifications act as detailed instructions, communicating the required level of quality for materials, systems and workmanship. In the event of discrepancy, specifications can take precedence over drawings. In other words, they are decisive.
This article explores how to use the specification as a deliberate health and sustainability tool. The specification, in an ideal world, can be seen as a system-level instrument for physical health, mental wellbeing, environmental regeneration and long-term resilience.
WHAT HEALTH OUTCOMES ARE INFLUENCED BY THE SPECIFICATION?
Architectural specifications for healthy buildings sit at the intersection of design intent, construction reality and long-term human health. They can therefore be seen as public health documents.
Some of the health outcomes influenced by Architectural Specifications include:
Respiratory health, via VOC limits, moisture control, ventilation standards, etc.
Thermal comfort, via insulation, airtightness, heating performance, etc.
Mental wellbeing, via daylighting requirements, acoustics, incorporation of nature, features for psychological safety, etc.
Energy levels and cognitive performance, via lighting design, ventilation, air quality monitoring, etc.
Musculoskeletal health, via ergonomic design, active furniture provisions, design for all abilities, etc.
Social health, via inclusive design and community-facing spaces, etc.
Healthier planet, via embodied carbon, biodiversity, resource efficiency, etc.
Chronic disease prevention, via health-supporting kitchens, frequent fresh drinking water points, air pollution reduction, etc.
Etc.
These are just some examples of hundreds of architectural specification solutions to improve human health and everyday wellbeing.
The specification becomes a public health document when it explicitly links clauses to measurable human outcomes.
EMBEDDING HEALTH IN PRELIMINARIES AND PROJECT REQUIREMENTS
The most powerful health decisions are made early; and specification writing should begin at Concept Design stage. NBS has recently launched an ‘early-stage specification library’ for outline specifications.
The NBS Best Practice Guide to Specification Writing emphasises coordination, clarity and alignment with design responsibility matrices. Health and sustainability objectives must therefore be embedded within:
Preliminaries
Employer’s Requirements (ER’s)/ Client Requirements
Design Responsibility Matrix (DRM)
The Works Sections
Health and Sustainability in the Preliminaries
Within the Preliminaries sections:
A — Consider measurable performance targets that need to be met at different stages of project life:
at completion of Enabling Works
during construction
before handover
when the building is in use.
The measurable performance targets can include, among other things:
Air quality - indoor and outdoor
Water quality
Lux levels
Moisture levels
Sound levels, acoustic performance
Temperature, overheating
Ventilation rates
Energy use
Air-tightness
Heat loss, thermographic surveys
Acoustic performance
Occupant evaluated building performance (post-occupancy evaluation - POE)
Any specific KPI’s - key performance indicators - that were identified at early project stages
With sophisticated building management systems (BMS), ‘internet of things’ (IoT) technology and smart building sensors, many more metrics become measurable, such as live carbon footprint, material lifespans, structural health, room occupancy data, circulation flows, waste streams, etc.
Etc.
B — Require commissioning of building systems; and seasonal re-commissioning.
C — Define substitution rules (i.e. if contractor proposes changes to materials or products during construction) that protect health performance
Avoid ambiguous language such as “or equivalent”. As noted in the NBS ‘Best Practice to Specification Writing’ guide, equivalency must be clearly defined and substitution processes set out in the Preliminaries to prevent dilution of performance standards. Note that “equivalent” substitutions may not be equivalent, for example, in terms of emissions, durability or microbiological risk.
Health-critical elements should be identified as non-substitutable without a formal health impact assessment
D — Address risks of value engineering, define agreed procedures in advance, ideally safe-guarding key health and sustainability goals.
Healthy building goals can easily fail if materials and products are substituted or during value engineering, despite best intentions at earlier project stages.
E — Clearly state strategic health and sustainability goals, outline high-level certification, ESG, insurance requirements, key guidance documents, client-specific requirements, etc.
F — Specify inspection frequencies and client sign-off stages.
G — State any handover procedure requirements, such as Soft Landings, etc.
The preliminaries generally describe a more strategic approach to the project than the Works sections. They also include anything that cannot be costed by the Contractor on the basis of drawings, schedules and specification Works section alone - for example, certification requirements, such as WELL, Fitwel, BREEAM or Passivhaus.
These items are an example of what should be considered for the Preliminaries from a healthy buildings perspective, in addition to the usual Best Practice content.
MATERIAL HEALTH AND INDOOR AIR QUALITY
Indoor air quality is one of the most directly specifiable determinants of health.
The NBS Sustainable Specification Guides align health goals with UN Sustainable Development Goal 03 (‘Good health and wellbeing’). In practical specification terms, this translates into clauses covering:
Low-emission adhesives and sealants
Formaldehyde-free composite timber
Prohibition of certain flame retardants
Moisture-resistant detailing to prevent mould growth
Etc.
Note that all prohibited materials and toxins should be clearly stated, including ‘legacy materials’ such as asbestos and lead, materials and toxins restricted by legislation, other toxic materials (e.g. those on the International Living Future Institute’s ‘Red List’ of ‘Worst in Class’ materials) and emerging pollutants. The list should be reasonable, however, and compliant material/product manufacturers should be identified. It will likely be impossible to avoid all toxins so priorities should be identified depending on building use, project goals, any vulnerable user groups and occupant special needs.
Material and product specification for healthy buildings is a vast topic which is outside the scope of this article; but avoidance of toxins (including off-gassing); durability; ease of maintenance; circularity; low embodied carbon; biobased and regenerative materials; as well as ethical and responsible resourcing are among the key considerations.
PRACTICAL PERFORMANCE SPECIFICATION STRATEGIES
From a specification writing perspective, continuity (from concept stage to completed building) begins by translating abstract health aspirations into measurable, enforceable requirements. Performance criteria should be explicit and include, for example:
Determination of which parts of the specification should be ‘prescriptive’ and which ‘descriptive’ sections/ clauses.
Requirement for third-party certification for materials and products, where appropriate.
Specification guidance from the NBS (2008) states that “standards are often cited but rarely verified”. Whether or not this is still the case, it’s important to require evidence of compliance.
Detailing of post-installation commissioning requirements, including duct ‘flush-out’ procedures.
Detailing of performance, testing, sample and mock-up requirements. (Require IAQ testing before handover, etc.)
Statement of any specific competence and training requirements.
Determined Handover procedures, Building User Guide requirements, Cleaning and Maintenance Strategy requirements, as-built survey requirements, etc.
Etc.
THERMAL HEALTH
Thermal comfort is both a human and planetary health issue. Thermal health in buildings is an extensive topic, encompassing heating and cooling strategies, moisture management, ventilation, prevention of overheating, energy-efficiency, carbon efficiency, adaptability of environments to individual user needs, personal comfort systems, air-tightness and breathability of the building fabric, passive systems (heating, cooling, ventilation), thermal therapies, climate and microclimates, wind modelling, etc.
Key Specification Actions in Relation to Thermal Health:
Consideration of passive heating, cooling and ventilation systems.
Energy-efficiency and renewable energy.
Fabric-first approach, insulation, U-values.
Building skin performance and layers understood: Air-tightness, breathability, ‘vapour open’ materials, etc.
Choosing the optimum heating, cooling and ventilation systems for comfort, adaptability and energy-efficiency.
Energy modelling.
Thermal bridge calculations.
Dynamic overheating modelling.
Whole-life energy and carbon reporting.
Energy performance certification requirements.
Moisture management: water and moisture in:
air (indoor air moisture monitoring)
under ground (ground water)
surface water (SuDs, etc.)
rain and storm water
moisture in materials
plumbing systems, leak detection
nearby watercourses, flood risk
etc.
Etc.
The NBS Sustainable Specification Guides include many of the above, and align the solutions with both the UN Sustainable Development Goals and specific Uniclass clause references.
Healthy thermal environments reduce cardiovascular stress, improve cognitive performance and reduce energy poverty risk, among many other benefits.
ACOUSTIC HEALTH, STRESS REDUCTION AND COGNITIVE PERFORMANCE
Noise is a physiological stressor. Chronic exposure increases cortisol levels and impairs concentration.
Specifications must articulate acoustic intent clearly, including the need for specialist input, where required.
Architectural specifications should address:
Mitigation of noise pollution from both outdoor and indoor sources, including noise from building equipment and systems, etc.
Sounds insulation levels appropriate to building use and each room type.
Acoustic performance of materials and build-ups, e.g. windows, doors, internal partitions, ceilings, floors, glazed screens, acoustic panelling, etc
Impact sound, airborne sound, reverberation, flanking transmission considered.
Acoustic detailing.
Vibration isolation details.
Reverberation time targets.
Etc.
Acoustic engineering is a complicated science and a Specialist Acoustic Engineer involvement in projects is recommended for best results. Importantly, performance standards should not be mixed or ambiguous and coordination with manufacturers’ test data and standard details is important. Workmanship standards must also be clearly included and measurable.
INFORMATION CONTINUITY FROM DESIGN TO OCCUPATION
Too often, health intent erodes between RIBA Stages 2–4 and practical completion. Substitutions occur; installation quality varies; commissioning is incomplete; and handover documentation fails to communicate the building’s operational logic. Healthy buildings can fail when health intent is not contractual and when substitutions are not tightly controlled. Information continuity is therefore the mechanism by which health objectives survive procurement pressures, value engineering and sometimes fragmented delivery processes.
Information continuity is not only about what is specified, it is also about how compliance is verified. Healthy buildings are complex systems (1). A discontinuity between envelope airtightness and ventilation commissioning, or between moisture detailing and on-site sequencing, can undermine health outcomes.
Requirements for testing, competency, performance verification, inspections, etc. reduce “failure pathways,” a concept discussed in the book “Sick Building Syndrome” by Rostron (2), where chronic building failures persist for decades because they are embedded during construction and cannot easily be corrected later. Moisture traps, poorly installed vapour control layers, inadequate flushing of ventilation systems — these are specification continuity failures with direct health implications, including mould growth and poor air quality.
CULTURAL SHIFT: THE SPECIFIER AS A HEALTH STEWARD
Specification writing is part of the design process and should be done by designers, as noted in NBS specification guidance from 2008. Specification writing is ethical work.
Architectural specification is a potent tool but a shift in perspective is needed:
From specifying products to specifying outcomes
From minimum compliance standards to health optimisation
From fragmented clauses to systems thinking
The architectural specification is possibly one of the most underestimated public health instruments in the built environment.
CONCLUSION
This introductory article has touched upon some of the key topics to address when specifying a healthy building. In addition to the healthy building categories discussed above, water quality, lighting design, daylight levels, design for active living, incorporation of greenery, atmospheres, multi-sensory design, safety, pest control and any relevant smart building features should also be addressed in the specification, among other things.
This article assumes that you are already experienced in specification writing and that you rely on a template system such as the NBS to construct the specifications. Therefore this is not an introductory article on how to write a specification, but on what to add for a healthy building specification. And even then it’s only scratching the surface.
Where to find and how to select products and materials for a healthy building is another topic which is not yet revealed here, as the topic deserves a series of articles of its own. If you’d like this (or another healthy building topic) addressed as a priority, let us know in the comments or via the contact form on this site.
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Architectural specifications are a mechanism through which values become reality. They capture a moment in time, a coordinated design vision, and together with the drawings translate an abstract visionary idea into a concrete form. When written with clarity, coordination and measurable intent, they infuse drawings and buildings with breathable air, comfortable temperatures, restorative acoustics and socially nourishing spaces.
Healthy buildings as complex systems demand multidisciplinary collaboration. Clients, local governments, architects, engineers, sustainability consultants, public health professionals and contractors must align around shared outcomes. The specification, especially when started early in the building design process, can then become an effective tool to capture, coordinate and realise a collective vision.
DISCLAIMER
We will not accept any liability for the use or misuse of this information. We can provide formal architectural advice only when appointed on a project.
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1) Riadh Habash, “Building as a System”, Sustainability and Health in Intelligent Buildings, Woodhead Publishing, 2022, pp. 1-32, ISBN 9780323988261
2) Rostron, Jack: “Sick Building Syndrome: Concepts, Issues and Practice”, Routledge 2005.
3) The NBS Sustainable Specification Guides
4) Construction Project Information Committee (CPIC): “Production Intormation: A Code of Procedure for the Construction Industry”, 1st ed., 2003