ASHRAE Journal - July 2019 - 12

TECHNICAL FEATURE

different environmental conditions.
FIGURE 2 Three groups of factors affecting thermal comfort for patients.4
Furthermore, some health-care procedures expose patients and staff to
Medical Condition
unique environmental and personal
conditions (activity, clothing, posHealthy
Disabled
Unhealthy
ture) that demand special attention
Physical/Physiological
Intellectual
and care to address thermal com* Impaired Mobility
* Impaired Perception
* Impaired Thermal Sensation
* Impaired Emotion
fort. There are three main types of
* Impaired Thermoregulation
* Impaired Cognition
* Impaired Metabolic Functions
* Impaired Temperament
representative occupants in health
* ...
* Impaired Adaptation
care (Table 1).
* Medical Staff Assessing therAge Group
Type of Service/Medical Procedure
mal comfort of medical staff faces
* Ward/Room Type/Location * Activity/Posture
* Newborn
* Adolescent
two fundamental challenges: 1) Ob* Adult
* Medicine
* Clothing/Gown
* Baby
* Elder
taining clothing and activity values
* Anesthesia
* Length of Stay
* Child
for comfort analysis is limited and
outdated. Health-care staff typically
wear task-specific uniforms for sanitary or protective reasons. For example, while surgeons
identifies the need for awarding special consideration to
wear gowns, hats, and gloves, support staff working in
the comfort of patients beyond Standard 55-2017.
decontamination areas wear highly protective clothing.
* Caregivers and Visitors Identifying caregivers and
2) Obtaining data on activity duration and location of
visitors as representative occupants depends on their
medical staff also poses challenges. Many of the medical level of involvement with the patients, and their presstaff have varying activities during a typical day (tempo- ence in the space. The prediction of thermal comfort for
ral transients) and often spend less than 15 minutes in
this group of occupants poses no unusual challenge.
a given room (spatial transients). The effect of transient
For all occupants concurrently occupying a space in
conditions on thermal comfort could become important health care, the personal and environmental condias the body takes time to adapt to new conditions. Actions often differ to a large degree. One example is a
cording to Standard 55-2017, a representative occupant
patient room where nurses, doctors, and guests visit
is "an individual or composite or average of several individuals
the patient regularly. Another example is the concurthat is representative of the population occupying a space for 15
rent occupation of an operating room (OR) by the
minutes or more." The purpose of the time requirement
patient, nurses, surgeons, and anesthetists. The clothrecognizes that it takes the human body time to adjust to ing worn by the medical staff often differs, as does the
the environment.
activity level, and even the microclimate where each
* Patients Standard 55-2017 specifies thermal envioccupant is located. According to Wyon,6 the only way
to reconcile the differences in thermal needs between
ronmental conditions acceptable for healthy adults. It
patients and medical staff is through clothing adjustdoes not apply to occupants who are sleeping, reclining
ments. However, clothing adjustments are often not
in contact with bedding, or able to adjust blankets and
bedding. Accordingly, most patients should be excluded feasible when medical procedures require specialized
protective clothing.
from consideration by Standard 55-2017. However, the
A key consideration in thermal comfort analysis is
term patient is broad; for example, day clinics serve
predicting the thermal comfort requirements from each
patients that are not necessarily sick. It is necessary to
representative occupant, which permits the developpay careful attention to patients' medical conditions (as
ment of an occupant-centered environmental design
indicated in Figure 2), when considering them as potenstrategy. Room thermal environmental technologies
tial representative occupants. Excluding patients from
and personalized comfort systems (PCS) have been proStandard 55-2017 analysis does not mean their thermal
comfort needs are not considered. Quite the opposite. In posed as a promising example to settle individual therthe context of health care, the statement above explicitly mal comfort differences, to enable less uniform indoor
12

ASHRAE JOURNAL

ashrae.org

J U LY 2 0 19

https://www.ashrae.org/

ASHRAE Journal - July 2019

Table of Contents for the Digital Edition of ASHRAE Journal - July 2019