New diagnostic and treatment equipment occupies dedicated spaces. At the same time, there is increased emphasis on ambulatory care for many procedures and illnesses, with more selective inpatient admissions and decreased length of stays. There also is a trend toward networking remote primary care and diagnostic centers to other types of care facilities.
With these changes comes the need to provide more sophisticated HVAC, power, telecommunications/data and life safety systems. Owners, architects and engineers alike face the challenge of allocating space and developing a facility infrastructure that not only accommodates these systems but also allows optimal integration and flexibility today and in the future.
To meet the demands placed on system infrastructure and to provide future flexibility, space must be allocated for much larger mechanical, electrical and telecommunications distribution hubs and risers. One of the biggest problems in existing facilities, which may be 30, 40 or 50 years old, is finding and reprogramming enough space to revamp the entire core infrastructure and controls. In new facilities, owners may be understandably reluctant to add to the amount of space required for the engineering systems.
Indeed, the proportion of the cost of the building systems to the total cost of a new facility is now approaching 50 percent. Whether planning an upgrade or new construction, finding cost-effective solutions requires cooperation among owners, architects and engineers.
Optimizing the HVAC System
Energy efficiency, indoor air quality, comfort and flexibility for future changes are the key criteria to keep in mind when engineering the HVAC system, which must provide the optimal environment for a range of treatment and support spaces.
HVAC systems today comprise more individual units dedicated to meeting the different temperature and air-quality needs of spaces such as telecommunications/data equipment rooms, diagnostic equipment rooms, operating rooms, emergency rooms and in-patient rooms. Zoning also allows the mechanical engineer to employ specific tools, such as high-efficiency air filters, where they are needed.
To assure indoor air quality, the HVAC system must be able to provide proper filtration and ventilation, and minimize cross-contamination of building spaces. Airflow must be directed from clean areas to less clean spaces and then exhausted outside. Controls must use a reliable monitoring and alarm system to ensure maintenance of proper indoor air quality and pressurization standards.
"All-air" HVAC systems, which allow use of primarily outside air to, whenever possible, heat and cool a facility, enhance indoor air quality and the energy efficiency of the HVAC system. Efficient motors, variable speed drives and economizer cycles all can be used to minimize energy consumption.
In any case, HVAC systems are heavy energy consumers. But deregulation has provided the opportunity to use systems that can use multiple energy sources to run boilers and produce chilled water. At any given time, the facility can choose which energy source to use (electricity, natural gas or steam) depending on demand, cost and availability.
The nature of today's hospital demands selection of state-of-the-art direct-digital-controlled HVAC systems, which are accurate and flexible, allowing control from central and remote locations.
Power: Quantity and Quality
Flexibility of power system infrastructure and power quality are key criteria for the electrical power system design. Spare capacity has to be built into every major normal and emergency power riser. In most cases, minimum code-suggested values for feeder and equipment sizing may not be adequate for modern hospital design because of universal usage of computer equipment for a wide variety of functions.
The nature and sheer volume of hospital systems and equipment also create challenges. For example, more and more equipment today is electronic, which contributes distortion to the electrical system. Current causes this distortion and voltage harmonics that affect both normal and emergency power supply and distribution systems, and sensitive medical electronic equipment fed from it.
To minimize harmonic effects on the power system, 200 percent neutral should be the standard on all three-phase, four-wire systems and equipment. Rectifiers and trap filters are strongly recommended on all variable frequency drives. Emergency generator specifications have to include provisions for 100 percent non-linear loads. Usually, generators will have to be one size larger than the engine size to compensate for non-linear loads.
The high volume of electrical equipment also creates electromagnetic interference. This is not the place to try to economize on construction costs. Electrical engineers often recommend rigid steel conduits for major feeders - especially those passing through critical areas - rather than the thinner, less expensive electrometallic tubing, which does not block magnetic interference.
The ratio of emergency to normal power is increasing. The trend is to place more systems on the emergency generator than dictated by minimum code requirements. For example, cooling is not required to be on generators, but more hospitals are electing to do so. Indeed, owners of facilities designed to meet code and budget requirements just a few years ago now may want to add systems to the emergency generator, only to find that their generators do not have adequate capacity.
Internet, Telemedicine Make the Call
The design of the telecommunications infrastructure in hospitals today is driven by the expanding need for high-speed, high-quality computing and networking both within the hospital facility and between the hospital and the outside world.
Hospitals already have in place or are adding new local area networks (LANs), often Ethernet systems, to network all types of data, from patient records to radiology data, throughout the facility. Now networks are expanding, with installation of data ports at each bed, allowing access to view and update patient records as well as diagnostic images. (The future is in wireless, portable access via hand-held computers, already being seen in some applications.)
Expanding the network to each bed necessitates upgrading the infrastructure to comply with the latest standards. This, in turn, requires telecommunications closets to be dispersed throughout the building, with certain distance limitations between the closets and each data outlet and certain closet size requirements based on the size of the area and the number of outlets.
Meeting these standards and future needs requires a lot of space and, when upgrading an existing facility or planning a new facility, owners and planners must be prepared to allocate it. Usually this space is in the core of the building, not in an underutilized corner, to meet distance requirements.
The good news is that current standards in the design of the telecommunications infrastructure should serve health care facilities well for 10 to 15 years.
This means that - even if new cable itself may be required in the next decade - the number and spacing of telecommunications closets should remain consistent - the crucial issue in space planning. Indeed, many believe that the next generation of cable will be "all we will ever need" in copper cable. Additional speed will have to be accommodated using fiber-optic cable.
The logical extension of the LAN is a wide-area network (WAN) that enables telemedicine: remote access to patient records, diagnostic images and other data by computer, with the capability of simultaneous videoconferencing. A lot of institutions are talking about telemedicine, and some are forming pilot projects. Some are making the connections between the hospital and physicians' offices and outpatient clinics over the Internet. Others are using dedicated T1 or ISDN phone lines, which offer higher-bandwidth (i.e., high quality) communication as well as quick speeds.
In fact, much of the capability for the WAN depends on the main telecommunications equipment in the building and the cabling that goes out to the world. Many hospitals have multiple T1 copper phone lines coming in and some fiber-optic cable. The trend is to bring in more fiber, which is what is really needed to drive video imaging. Either way, space is needed in the main telecommunications room for the large amount of equipment to communicate with remote sites.
Life Safety, Security
As it is in emergency power, so it is in life safety: The trend is to exceed code in both existing and new facilities. Many existing hospitals have outdated fire alarm systems and inadequate sprinkler systems by today's standards. Owners are retrofitting with modern, computer-controlled fire alarm systems - centrally monitored and controlled from a fire command station, usually in the main lobby.
The new systems require new water service, fire pump and vertical distribution system and additional sprinklers. This complicates the cost and space issues. A sophisticated mechanical system can also provide smoke control, either automatically or manually from the fire control station. This is a highly reliable early warning system.
Security systems are vendor-driven, changing rapidly, and are generally planned and implemented after a building is completed. Much of a security installation is low voltage. Thus, engineers should assure that enough space and power are allocated in the backbone for security hub equipment. Needs differ, but most security systems today use some combination of card access and biometrics readers, motion detection, closed-circuit television and metal detectors, as well as personnel.
Higher Demands
It's also worth mentioning that stand-alone ambulatory care facilities may place even higher demands on infrastructure because there is more sophisticated equipment packed into them than in some hospitals, which contain patient rooms and more support spaces.
Now, what about controls? Given the size and complexity of the hospital setting, integrated controls would seem to offer distinct benefits. Yet it is not only expensive but often difficult to build a system that integrates control of all mechanical and electrical systems because many control manufacturers' systems are proprietary.
There has been an effort in the market to develop "open protocol systems" - creating an integrated control system - but applications have involved links between components or subsystems rather than completely integrated automation systems. Today, it is more common to selectively marry major control components to the building management system regardless of whether the controls use open protocols. Continued introduction of products that use open protocols promises to expand the use of integrated control systems.
In the final analysis, designing a health care facility infrastructure for the 21st century is all about optimizing system integration and flexibility to ensure that the facility will remain a fully functioning organism in the future. Perhaps nowhere else is the metaphor of infrastructure as "backbone" more apt than in health care.
