By Matt Lee / Special to Healthcare Facilities Today

Maintaining a proper climate is important for any building, but certain facilities have much more challenging needs.  A significant aspect of climate control within a hospital setting is the control of moisture levels, both in the interior and exterior of the building.

Not only are hospitals subject to exterior moisture control problem, just as any other building structure, but they also tend to have rooms within the building that already have high humidity and must be properly maintained. The nature of hospitals can cause humidity or air-moisture levels to spike and without proper control it can lead to structural damage as well as negative health effects for patients and staff. It also goes without saying that proper air ventilation and clean air circulation is vital for maintaining health in such an enclosed setting.

Ensuring that the physical building itself is properly designed is a major step in controlling all aspects of moisture.

Designing an improved building envelope

One of the most significant aspects of moisture control within a hospital is the building envelope, which is simply the exterior of the hospital. The exterior walls not only serve as a protective barrier against damage and harsh weather, but also serves as a barrier between outside temperatures, air quality, and even noise pollution.

Newly constructed buildings or those being renovated should be constructed with concrete block wall systems or similarly designed concrete walls. Concrete walls are a common exterior wall for hospitals but aren't as advantageous as you'd expect. Insulated concrete block walls are less expensive, faster to install, have far better insulation against outdoor air temperatures, and even help buffer outside noise. These walls are perfect for hospitals and will aid in proper moisture control.

These types of wall systems may also be used for interior room walls where climate control is especially vital, such as exam, surgery or surgery-prep rooms.

Other important design guidelines for the building envelope include:

• Installing flashing on concrete block walls during construction

• Selecting a siding material designed repel water, such as fiber-cement

• Choosing a durable, water-resistant roofing material, such as aluminum or steel

• Sloping ground away from the hospital building to allow for proper drainage

• Installing proper gutters from rainwater control

One of the biggest reasons why moisture ends up causing damage is a lack of regular maintenance. The build should be regular inspected, including the roof, on a schedule as well as after any significant weather event (i.e. a heavy rainfall or windstorm).

Select high-quality building materials whenever possible, especially when it comes to regions with heavy annual rainfall and high humidity.

Addressing indoor moisture control

Even with a high-performance, immaculately designed building it is still possible for hospitals to experience moisture damage due to uncontrolled indoor environments.

Hospitals naturally have fairly stringent requirements for air quality. HVAC requirements should maintain indoor temperatures at 68F to 75F and a humidity of 30% to 60%. HVAC systems that are in place should have a very high ventilation rate, at upwards of 20 cycles per hour. These needs are ideal for majority of hospital exam rooms and waiting rooms, however, specialty room may have even more specific needs.

For example, proper moisture and overall climate control is vital in radiology suites as well as post-op rooms. Radiology rooms may need to have temperatures up to 80F and a humidity level of 40%. Post-op rooms are also very important as patients recovering from surgery are very vulnerable and unable to properly maintain their own body temperature. Humidity in these rooms shouldn't exceed 55% and temperatures should be kept fairly steady at 75F.

Some other design ideas for moisture control indoors include:

•  Adding a continuous air barrier system in place to control moisture and prevent condensation

•  Installing special curtain systems to prevent condensation in high-humidity rooms

•  Installing interior airtight partitions to control airflow and moisture within multi-purpose rooms

•  Limiting "wet" rooms (i.e. a larger bathroom versus numerous smaller bathrooms)

•  Careful control over humidity levels in hot climates

•  Proper exhaust of "wet" rooms to the outside

It it vital that hospitals be designed with the importance of moisture control in mind. These healthcare facilities are prime ground for infection, particularly airborne infection, which can flourish when moisture is not kept at specific ranges. Ensuring that the building envelope is secure will help interior climate settings be easier to control, along with the assistance of updated HVAC systems.

Any issues that develop with too high humidity or condensation development must be immediately addressed in order to prevent issues with machinery as well as maintain proper air quality health for people within the building.

References:

• Moisture Control - Department of Energy

• Moisture Control Guidance - Environmental Protection Agency

• Moisture Control for Buildings - Building Science Corporation

• Moisture Control and Ventilation - WHO Guidelines for Indoor Air Quality