Atecyr’s DRA and the Spanish landing of the UNE-EN 16798 approach in tertiary

• Post Author:Marketing
• Post published:20 January, 2026
• Post Category:Blog

How a proposal in Annex-A for UNE-EN 16798 -1 can resize facilities, shift costs and open the debate on the purification of recirculated air. ATECYR’s DRA 010804 lands UNE-EN 16798-1 in Spain and changes the focus: “outside air per person” is no longer enough. By introducing the “building” component and assuming LPB3 by default, you can resize facilities, shift costs, and reopen the debate on recirculated air purification.
 

Atecyr’s DRA and the Spanish landing of the UNE-EN 16798 approach in tertiary

Table of Contents

• Atecyr’s DRA and the Spanish landing of the UNE-EN 16798 approach in tertiary
  • Framework in force in Spain: RITE + UNE EN 13779:2008 (and CR 1752)
• What is “UNE 16798” and what is “DRA”: avoid confusion
  • UNE-EN 16798 defines the method, the “how”
  • The DRA gives proposed values and application guidance, defines the “how much”
• What does the DRA 010804 (Atecyr) introduce and how does it differ from the “standard use” of 16798 1
  • The real disruptive point: LPB3 by default “takes out” the operating cost of the machine room
• Comparative example: RITE vs DRA: LPB-1, LPB-2 and LPB-3
  • Designer External Flow
  • Annual energy impact (ventilation and outdoor air conditioning only)
• Air cleaning: technically defensible, still immature (the bottleneck is gases)
• Conclusion: why this matters to the tertiary
• Practical recommendation to apply today in projects (without waiting for regulatory changes)

Framework in force in Spain: RITE + UNE EN 13779:2008 (and CR 1752) 

For years, in “general” tertiary (offices, commerce, teaching, non-special leisure, etc.), ventilation has been dimensioned, in practice, with a dominant question: How much outdoor air per person? 

The UNE-EN 16798 family of standards introduces a modern methodological framework: the design flow is understood as the sum of what people contribute and what the building contributes (finishes, furniture, future changes), or even the terrain and that integrates health, source control and verification/monitoring. The “change of method” is here.  

Atecyr’s DRA does not change the method: what it does is propose specific national values and complete parameters for Annex-A of the standard, which would be “open” or difficult to apply in the project. 

 This distinction is not academic, but explains why the DRA can facilitate a future convergence of the RITE towards UNE-EN 16798 without remaining in an incomplete or interpretative transposition. 

 The most relevant consequence for the sector is not technical; it is economic and contractual: indoor air quality and its associated energy are no longer an exclusive matter of HVAC and now depend, in a quantified way, on ownership, architecture and interior design decisions . 

The DRA 010804 is a free document and can be downloaded free, along with the rest of the DRAs, from the ATECYR website: DRA – Atecyr Reference Document 

What is “UNE 16798” and what is “DRA”: avoid confusion 

UNE-EN 16798 defines the method, the “how”  

The UNE establishes a framework by categories (quality of the indoor environment) and a methodology that, in ventilation, tends to separate: 

• component by occupation (bioeffluents and human activity), and 
• component by emissions of the building (materials, finishes, furniture). 

That methodological change is from the UNE. 

The DRA gives proposed values and application guidance, defines the “how much”  

El DRA aporta una evolución relevante: desplazar el foco desde la ventilación “por persona” (típica de la UNE-EN 13779 en el RITE actual) hacia un enfoque combinado que suma contribuciones por ocupación y por superficie, ligando específicamente las necesidades de ventilación a la carga contaminante del edificio y, por tanto, a sus acabados interiores. Esta perspectiva, bien instrumentada, permite alinear salud, confort y energía, y asignar responsabilidades medibles a arquitectura y propiedad sobre el costo operativo del edificio. 

Providing a technical bridge to the EPBD by connecting air quality, building emissions and operation, the DRA aligns with the EPBD’s approach: energy efficiency cannot be assessed in isolation, but in conjunction with indoor environmental quality and the ability to measure and maintain those conditions. 

What does the DRA 010804 (Atecyr) introduce and how does it differ from the “standard use” of 16798 1 

It maintains the minimum sanitary (≥4 l/s·person) and the logic of adjustment for ventilation effectiveness, consistent with 167981. 

• It adopts flows per person for bioeffluents in three categories (I/II/III), in line with the spirit of 167981:
  • Cat I ≈ 10 l/s·person; Cat II ≈ 7 l/s·person; Cat III ≈ 4 l/s·person
    (These values are consistent with the examples/tables of 167981) 
• Formally enter the “building component” (qB) and, here’s the lever: the DRA states that “by default” a building would be “non-low-polluting (LPB3)” unless otherwise justified with material/emission control.
  • This decision is much more than semantic: LPB3 implies high qB, therefore more base ventilation or the need for source control (certified materials, etc.). 
• • 167981 contemplates building categories and gives criteria, but the DRA makes a conservative default assignment, which in Spain can be very reasonable for “real” tertiary (fitout with rotation, furniture, carpets, adhesives, etc.). 

• • Define the justification by calculating in UNE-EN-16516 and define specific values 
• CO₂ ceases to be “the IAQ” and becomes a partial indicator (bioeffluents), with a practical obligation to look at VOC/PM/radon (at least as a risk or audit criterion). It establishes the values 550/800/1350 ppm outdoors as a category reference (different from the RITE values) and also requires consideration of other pollutants with clear references to the WHO tables. It explicitly incorporates the WHO Air Quality Guidelines Guide, where there are no other more demanding national reference values 
•  In general tertiary, the proposed annex guides the use towards calculation by components (UNE methods 1 and 2), leaving method 3 (predefined flows) as a residual route unless specifically justified. 
•  For high-risk scenarios, the DRA refers to specific design and operation criteria for the risk of airborne infection, linking to other Atecyr documents (e.g., DRA 010201). 
• Complementary criteria that land the CAI in the project and the operation:
  • Permissible air velocity in occupied area. The DRA adds something very practical: under limited conditions (especially in summer and with control by the user or in spaces with people in motion), it proposes to admit higher speeds in occupied areas as a tool to improve thermal sensation. In terms of efficiency, increasing air movement can allow somewhat higher cooling setpoints without degrading comfort, reducing consumption and emissions 
  • Temperaturas/humedades en edificios sin acondicionamiento mecánico. Aunque el DRA incluya criterios adaptativos claros para edificios sin acondicionamiento mecánico, cuidado en centros de trabajo. La normativa laboral, PRL, introduce límites de temperatura más estrictos que en mi opinión, deben respetarse como referencia de aceptabilidad ordinaria: 
• • •  Trabajos sedentarios (oficinas, etc): 17–27 ºC 
    •  Trabajos ligeros: 14–25 ºC 
  • Pautas de ventilación previa y en desocupación, propone 1 renovación o la componente qB, durante las 2 horas previas a la ocupación 
• • Horarios de ocupación funcional para cálculos energéticos 
• • Referencia a valores guía (OMS) para contaminantes interiores a justificar. 
• • Y una puerta abierta al papel de la purificación del aire recirculado, pero no define un procedimiento equivalente al camino prestacional formal de ASHRAE 62.1-2025.  

El punto verdaderamente disruptivo: LPB3 por defecto “saca” el coste operativo del cuarto de máquinas 

En términos de mercado, LPB3 por defecto es una idea sencilla con efectos profundos: 

• Si no puedes demostrar que el edificio y sus acabados son de baja emisión (y que esa condición se mantendrá), el sistema se dimensiona como si el edificio “emitiera” más. 
• Eso aumenta el caudal de aire exterior y, con él, crecen ventiladores, baterías, conductos y recuperación. 
• El coste operativo (energía y, por extensión, emisiones) deja de depender solo de la ingeniería y desplaza el debate desde el ingeniero de HVAC hacia el promotor/propiedad, arquitectura, interiorismo y explotación: depende de qué se instala dentro y de quién controla los cambios. 

Ejemplo comparativo: RITE vs DRA: LPB-1, LPB-2 y LPB-3  

A continuación, se reproduce el mismo “tamaño” de ejemplo que figura en el DRA (100 m² y 10 personas con LPB2) y se extiende a escenarios de LPB1, LPB3 y a una comparación con un criterio “típico” de RITE/IDA-2. 

Hipótesis del ejemplo, (compatibles con el ejemplo del DRA) 

• Ubicación: Madrid (referencia) 
• Superficie: 100 m² | Ocupación: 10 personas 
• Altura: 2,7 m → Volumen: 270 m³ 
• Horas con ocupación: 1.800 h/año 
• Horas operativas edificio: 2.400 h/año (por horario laboral flexible) 
• Pre-ventilación (interpretación operativa): mínimo 1 renovación/h durante 2 horas previas a la ocupación 
• Recuperación sensible: 75% (supuesto típico) 
• Impulsión de aire al espacio a 18ºC en verano y en invierno. 
• Bomba de calor COP 3.5; EER 3 

Nota: el objetivo del ejemplo es comparar órdenes de magnitud, no sustituir una simulación reglamentaria.Caudal exterior de diseño

• LPB3 by default increases the flow rate by +50% compared to the DRA example (LPB2), and +65% compared to a “typical” IDA-2. 
• LPB1 allows you to be below the typical case in the hours of occupancy 

Znnual energy impact (ventilation and outdoor air conditioning only)

With the same simplified framework that we have been using, the annual order of magnitude is as follows: 

TheLPB2 → LPB3 jump is not a detail; it is a decision that, approximately, can lead to a ~1.5 fold increase in ventilation energy attributable to the building, EPnr energy and CO2 emissions. And that decision doesn’t depend on the fan or the heat pump: it depends on finishes and control of the interior. 

Air cleaning: technicallydefensible, still immature (the bottleneck is gases) 

In tertiary education, it is already common to hear: “I keep the outside air low and compensate with purification of the recirculated air”. The DRA leaves the issue open, but does not resolve it as a complete equivalence procedure.  

Here the DRA leaves the door ajar in the discourse, but does not define a procedure equivalent to the formal performance path of ASHRAE 62.1-2025 (mass balance, contaminants of interest, verification, acceptability, testing requirements and control of by-products). 

From a technical point of view, it is defensible (and consistent with the benefit approach of other frameworks) to propose a benefit strategy if two conditions are met: 

1. Standard Methodology for Determining “Equivalent Outdoor Air” Flow 
2. demonstrate concentrations under reference limits and acceptability 
3. Safety/by-product framework (especially for technologies beyond mechanical filtration and sorbents). 
4. verify in operation and useful life, that the system maintains efficiency without generating risks. 

It is advisable to separate by families of pollutants: 

• Fine particulate matter (PM2.5/PM1) and aerosols: mechanical filtration with verifiable efficiencies. 
• Total VOCs/formaldehyde: specific media (sorbents) with capacity, substitution, and control curves. 
• Microbiological (if included): Proven strategies for air/surfaces (not to be confused with VOCs). 

Real bottleneck: gases (VOCs/formaldehyde). Not because of “if it works”, but because of safety, by-products, and lack of a fully standardized framework (testing, monitoring, end of life) so that they can “count” as a partial substitute for outdoor air with general credibility.

Conclusion: why this matters to the tertiary  

The DRA is relevant because it puts figures to a reality that the sector knew in a vague way: the building and its interior finishes condition the flow, the size of the system and the energy. The LPB3 rule by default turns this reality into an incentive: either the interior is controlled and documented, or it is paid for with ventilation, power and consumption. 

The final message is not “more ventilation”: it is a better building (in indoor emissions), better governance of interior adaptation and, where innovation is desired, purification of recirculated air with method, verification and safety.

Practical recommendation to apply today in projects (without waiting for regulatory changes)

For general tertiary, a robust strategy (technical and regulatory compliance) is: 

1. Comply with RITE explicitly by category of use (IDA 2/3 typically) and method chosen (table or CO₂). 
2. Design with DRA/16798 logic as the “top layer”: 

• calculate qP + qB (and declare LPB3 if there is no evidence), 
• provide for demand-side control (CO₂ and, where applicable, VOCs); 
• and prepare a verification/measurement plan that can be aligned with UNE 171330. 

1. Document hypotheses (density, materials, schedules, pre-occupancy ventilation, etc.) as if you were going to EPBD inspection: because that world is coming. 

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If you are planning or renovating a tertiary building and you want to optimise ventilation, CAI and energy with criteria aligned with RITE and with the UNE-EN 16798-1/DRA logic (qP + qB, demand, verification), at Prointer we can help you turn these criteria into an installable and operable solution: design, execution, commissioning and performance improvement.

Contact our team and we will review your case (occupancy, finishes, control strategy, measurement and life cycle costs).