ASHRAE Journal - July 2019 - 11

TECHNICAL FEATURE

For thermal comfort purposes, the
patients' group can be further broken down into subgroups based on
the unique contextual personal factors. In Figure 2, three groups of factors affecting the thermal comfort of
patients have been identiﬁed from
the literature.4

Thermal Comfort in Health Care

FIGURE 1 The assessment of thermal comfort.

Health-Care Context
Health-Care Environment
Medical Service
Medical Service
Activity
Clothing

Objective
Measurements

Building Physics

Health-Care Environment
Health Condition

Medical Service
Health Condition

Physiology

Psychology

Thermal Comfort
Assessment
Subjective
Evaluations

ANSI/ASHRAE Standard 55-20175
provides methods to support therThermal Regulation
Personal Background
Subjective Scales
mal comfort analysis and design
* Age
* Social, Cultural, Economic
* Thermal Sensation
for buildings intended for human
* Gender
* Thermal History
* Thermal Acceptability
* Expectations on the Medical Service
* Thermal Satisfaction
occupancy. These methods are
* Expectations on the Indoor Environment * Thermal Preference
based on well-established principles, models, and comfort metrics
applicable to any
TABLE 1 Occupants and their health care thermal comfort factors.4
building intended
for human occuTHERMAL COMFORT FACTORS
MEDICAL AND SUPPORT STAFF
PATIENTS
VISITORS/CAREGIVERS
pancy. However,
applying Standard
Environmental
Medical/Support Service Speciﬁc * Medical Service Speciﬁc
Common Seasonal
Varied Control of the Thermal Environment: * Some Control of the
Thermal Adaptation
55-2017 to health care Air Temperature, Radiant
Multi-Occupant to Individual, High Air
Thermal Environment by
Temperature, Air Speed, Humidity
involves challenges
Speeds in Some Medical Procedures
Staff and Caregivers
that require special
consideration.
Common Seasonal
* Medical Service Speciﬁc
Personal
* Medical/Support Service Speciﬁc
Standard 55-2017
Thermal Adaptation
* Gowning/Bedding
* Limited Personal Thermal Adaptation
Metabolic Rate, Clothing Insulation
requires identifying
* Personal Thermal
* Required Clothing/Uniform
Adaptation
* Activity:
all spaces to which
*
Standing, Sitting, Lying,
Steady - Transient
the standard is being
Sleeping, Immobilized
applied, which
implies that Standard Other
Mental Stress, Fatigue,
Anxiety, Length of Stay,
Anxiety, Short Stay,
Workload, Performance, Arousal,
Health/Wellness Condition,
Support
55-2017 may not
Psychological, Work Related,
Health Condition, Well-Being
Age, Medication Impact,
Health-Condition
Related
apply to all spaces. In
Healing, Overall Comfort
some spaces, thermal
comfort is not the
driving factor for the thermal environment. Therapeutic at least one representative occupant shall be identiﬁed. If any
conditioning is needed for certain medical procedures,
known set of occupants is excluded from consideration, then
treatments, or healing processes that demand controlled these excluded occupants shall be identiﬁed." This implies that
environmental temperature and/or relative humidity
Standard 55-2017 may not apply to all occupants. The
conditions that deviate from the typical thermal comfort activity and clothing of staff and patients in health-care
conditioning requirements.1 HVAC designers must work facilities are tied to the medical service being offered/
with the health-care organization on the HVAC-related
received, which affects human thermoregulation and
thermal comfort requirements, and identify the spaces
heat transfer with the environment. While patients may
where occupant comfort is not the basis for the tempera- spend hours or days in a room, medical staff's daily
ture and humidity requirements.
activities are often transient: constantly varying activStandard 55-2017 speciﬁes that: "[F]or each space type,
ity levels and moving between rooms and wards with
J U LY 2 0 19

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ASHRAE Journal - July 2019

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