A GUIDE FOR HOSPITAL AHU REPLACEMENT

Alan E. Fritsche, Principal, Garner Fritsche Engineering

Alan E. FritscheLEED AP BD+C,

Principal

Objectives• System analysis considerations

• Minimizing down time (or Zero Down Time)

• Temporary AHU’s and ducting strategies

• Infection Control Risk Assessment (ICRA) planning

• C-Suite & Departmental buy-in presentation

• Implementation of the program

System Analysis ConsiderationsWhat components does the existing AHU have?

Make a sketch, take pictures• Cooling coil or coils; count the rows of tubes

• Heating coils

• Type of fan, quantity of fans, motor horsepower

• Blow thru or draw thru

• Horizontal or vertical

• Filters – get MERV ratings, number of filter banks location/position, size

• Control dampers, smoke detectors, UV lights, humidifier

System Analysis Considerations

Determine Capacity• Look for existing drawings, schedules

• Measure cooling coil size

• Space take-off; check HHSC 133 for code required amounts

• Outside air quantity

• Supply air temperature required

• Chilled water supply temperature available at the AHU

• Hot water supply temperature

• Air side static pressure required

System Analysis Considerations

Code Requirements• Most AHJ’s (City, HHSC) will require the AHU

system be updated to all current codes

• HHSC considers AHU replacements a minor project

Minimizing Down TimeHow long will AHU be down?

• Consider hours of operation for areas served

• Consult with contractor for duration estimate

• Temporary AHU may be required

• Season of year for project

Temporary AHU’s and Ducting Strategies

• Temporary AHU considerations:• Where will the temp AHU be placed?

• How many yellow flex ducts will be needed?

• Temporary ducts need to be insulated

• Most rental AHU’s DO NOT have final filtration option

• CHW, HW, electric services need to be pre-planned

Infection Control Risk Assessment(ICRA) Planning

• Get this department engaged as soon as possible

• Plan on temporary isolation walls • Negative air HEPA filtration

machines• Noise scheduling• Spot-cooler air conditioners

C-Suite & Departmental Buy-In Presentation• Infrastructure projects are generally needed, NOT

wanted

• Prepare for this meeting

• Benefits

• Lower energy consumption

• Better climate control = Patient satisfaction

• Bring up to current code standards keeps the facility compliant with HHSC, TJC/CMS

• Have a cost analysis

• Time frame of the project

Implementation

• Develop a full schedule for the project

• AHU’s are long-lead items

• Consider how the unit will get into the mechanical room

• Hire an engineer for system analysis

Don’t forget the 7 P’s

Questions?

Alan E. Fritsche, LEED AP BD+C, Principal

Garner Fritsche Engineering, Inc.

713.432.1422

afritsche@garnerfritsche.com

GarnerFritsche.com

mailto:afritsche@garnerfritsche.com