Energy Efficiency Opportunities in the OR

Transcription

1 Energy Efficiency Opportunities in the OR John D. Villani, P.E. Vice President, Grumman/Butkus Associates Laurence Steiner, P.E. Associate Vice President, Grumman/Butkus Associates BUILD. CONNECT. ACHIEVE. 0

2 AIA Quality Assurance The Building Commissioning Association is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 1

3 Course Description Hospitals are energy-intensive facilities, and energy represents more than half of the healthcare facility budget (according to the American Society for Healthcare Engineering). Saving energy in healthcare settings is the sum of many small steps, of which operating room setback can play an important role. This presentation will discuss the benefits of better management of airflow, temperature, and pressurization in operating rooms, which can result in significant cost savings for healthcare facilities. Learn about applicable codes and standards, as well as aspects of conventional wisdom that produce internal resistance to changes in environmental management. Case studies will provide real-world examples of safe and effective reductions of OR energy use via implementation of an occupied/unoccupied mode strategy for HVAC serving the OR. 2

4 Learning Objectives 1. UNDERSTAND cost savings potential from better energy efficiency in the operating room 2. LEARN typical concerns of owners, professional staff, and facilities staff 3. EXPLAIN the general design approach, pressurization relationships, and codes pertaining to operating rooms 4. EXPLORE various approaches to efficient cooling, heating, humidification, and airflow in the OR, including setbacks during unoccupied hours 3

5 Main Reason to Make ORs More Energy Efficient EPA estimates that the U.S. healthcare sector's current annual electricity use of 73 trillion kilowatt-hours (kwh) contributes $600 million per year to healthcare costs via increased asthma and other respiratory illness. Reducing energy usage reduces a hospital s operational costs and reduces a hospital s carbon footprint 4

6 Hospitals Are Energy-Intensive Facilities Challenge: Hospitals use two to three times more energy (per sq. ft.) than office buildings: 24/7 occupancy High airflow, filtration 5

7 Up to 375,000 BTU/SF/Yr 6

8 Range: as low as $1.50/SF/YR and high as $6+ /SF/Yr 7

9 Hospitals Are Energy-Intensive Facilities Opportunity: $50,000 reduction in energy costs is equivalent to $1 million in new revenues (assumes 5% ROS) Research by the EPA shows that hospitals that implement ECMs outperform competing hospitals by as much as 10% in net operating income 1 1. EPA Study, Boosting Your Bottom Line Through Improved Energy Use, June

10 Facility Energy Savings Saving a lot of energy is the sum of many small steps of which OR setback is one. Data on 10 hospitals in which retro-commissioning and other relatively low-cost energy conservation measures have been implemented: Annual energy costs reduced by $17,322 to $537,780 Annual energy costs reduced by 3.4% to 18.3% 9

11 ASHE Benchmarking Data: Cost Breakdown of Facility Budgets Energy represents more than half of the healthcare facility budget, according to current benchmarking data from the American Society for Healthcare Engineering. That s more than staffing, materials, and service contracts combined. Staffing 27% Materials 8% Service Contracts 14% Energy 51% 10

12 Energy Consumption and Potential Areas for Savings Airflow (ventilation) Heating/reheating Cooling Lighting and equipment Pumps 15% 15% Healthcare Energy Use 7% Airflow 34% Heat/reheat Cooling 29% Lighting/equipment Pumps Source: National Renewable Energy Laboratory study of healthcare end-use monitoring, August

13 Staff Concerns Perioperative hypothermia (<34.5 C impacts wound healing, cardiac events, drug metabolism, coagulopathies, etc.) It is a misconception that ORs are kept cold for infection prevention Rooms are usually kept cold for surgeon comfort Cooling vests are available to OR staff 12

14 OR Temperature Clinical Measuring body temperature and maintaining normothermia (36 C) is now the standard-of-care during prolonged general anesthesia. Core measurement requirement through 12/13 Patients under anesthesia have lowered auto-response mechanisms such as shivering and sweating to respond to high or low body temperatures. Mild perioperative hypothermia, which is common during major surgery, may promote surgical-wound infection by triggering thermoregulatory vasoconstriction, which decreases subcutaneous oxygen tension 1 1. New England Journal of Medicine,

15 Addressing Concerns Adjust engineering controls so that operating rooms and patient areas are not permitted to become excessively cold overnight, when many rooms are closed. Work with OR management to educate surgeons and staff regarding room temperatures and clinical outcomes 14

16 Accreditation Concerns 46% of all hospitals surveyed by the Joint Commission in 2013 received a non-compliant finding in EC EP6 Ventilation system is unable to provide appropriate pressure relationships, air-exchange rates, and filtration efficiencies Specific areas lack Negative or positive pressures in relationship to adjacent areas (i.e., operating rooms should be positive to the egress corridor) The correct number of air changes per hour Proper filtration 15

17 Essential Maintenance ASHRAE 180 Minimum Requirements A maintenance plan that describes the goals, objectives and execution of the maintenance program Inspection and maintenance tasks Inspection and maintenance task frequencies Condition indicators Documentation 16

18 Maintenance 17

19 Design, Codes, and Air Changes per Hour (ACH) 18

20 General Design Supply Air Laminar supply diffusers above surgical area HEPA filtration Supply air washes down over patient and away to corners of OR 19

21 General Design Return Air Typically, 2 or 3 low returns in the corners of OR on opposite sides 20

22 General Design Supply Air 21 SUPPLY AIR FLOW 21

23 General Design Return Air 22 RETURN AIR FLOW

24 General Design Supply And Return Airflow 23 SUPPLY AIR FLOW RETURN AIR FLOW

25 What s Wrong With This Picture? BACKWARDS BOX? 24 SUPPLY AIR FLOW RETURN AIR FLOW 24

26 General Design Supply & Return Supply CFM = 2,080 (260 x 8) Returns CFM = 1,800 (900 x 2) Air for OR Pressurization 2,080 1,800 = 280 CFM 25 SUPPLY AIR FLOW RETURN AIR FLOW

27 General Design Air Changes Per Hour OR = 502 Sq.Ft. 10 Ceilings = 5,020 FT 3 Supply CFM = 2,080 Air Changes per Hour (ACH) = 2,080 CFM x 60 (min/hr) / 5,020 FT 3 = 25 ACH = 25 ACH 26

28 Codes KEEP CHANGING.... To design and analyze healthcare facilities, the provider needs to be intimately familiar with the related codes and standards State codes IBC IECC ASHRAE AIA ASHE CDC NFPA NEC 27

29 ASHRAE Then and Now... 28

30 ASHRAE Then and Now... 29

31 ASHRAE Then and Now... 30

32 Current Applicable Codes and Standards ASHRAE/ASHE Standard for Ventilation of Health Care Facilities: Class B and C Operating Rooms: minimum 20 ach, minimum 4 ach outside air, positive Per Paragraph c: For spaces that require positive or negative pressure relationships, the number of air changes can be reduced when the space is unoccupied, provided that the required pressure relationship to adjoining spaces is maintained while the space is unoccupied and that the minimum number of air changes indicated is reestablished anytime the space becomes occupied. 31

33 State Codes in Wisconsin State of Wisconsin FGI and ASHRAE 170 Operating Rooms: Minimum 20 ACH, positive Other considerations ASHRAE-specified ACH are minimums. Actual occupied ACH can be higher if needed for cooling or to accommodate array size. Many ORs get up to 30 ach. 32

34 State Codes Can Differ from Standards/Guidelines Illinois Department of Public Health (IDPH) IDPH Part 205 for Ambulatory Surgical Treatment Centers Procedure Room: minimum 15 ach, positive IDPH Part 250 for Hospitals and Ambulatory Care Facilities Surgical Suite Operating Rooms: minimum 15 ach, minimum 20% outside air, positive Other considerations IDPH and ASHRAE specified ach are minimums. Actual occupied ach can be higher if needed for cooling. Many ORs get up to 30 ach. 33

35 Case Study 1 - Occupied OR Testing and Cx First tested ORs and found we could NOT meet a pressurization setpoint of 0.02 w.g. across OR door to sterile corridor Increased OR cfm offset ORs started with over 700-cfm offset due to absence of door sweeps or astragals and incomplete construction, such as the med gas column Used painters tape to test tightening the OR at the doors 34

36 Unoccupied Mode What Is Minimum ACH? Other considerations IDPH has stated to G/BA that it is acceptable to reduce OR air change rates to lower than 15 ach when the rooms are unoccupied, provided that the positive pressurization is maintained, and the air changes per hour is 15 ach when the room is occupied again. California Unoccupied 6 ach minimum 35 3

37 Unoccupied Mode What is Minimum ACH? G/BA data: RCx on 164 Ors, 8 hybrids, and 12 hybrid ORs Findings from this data: Most existing ORs can remain positive with 6 ACH. However, they will be just at code minimum of w.g. (Note: not ALL.) Normal stable unoccupied control can be found with 8 ACH, which is now our starting point for RCx projects Calibration, testing and trending MUST be done to confirm stable operation MUST consult with the Medical Staff and Infection Control Group within the hospital MUST provide means of switching back from unoccupied to occupied modes 36 36

38 Pressure Relationships OR must be positive to all adjacent spaces 37

39 Case Study 2 Room Pressurization is controlled by actual pressure 38

40 Case Study 2 Negative OR Pressurization Trending showed this happening 3 to 4 times per night per OR Neutral OR Pressurization 39

41 Case Study 2 Cx should help troubleshoot and offer results-based suggestions 3400 cfm 1700 cfm Added a stepped control loop to go from occupied to unoccupied mode in 300 cfm increments every 5 minutes 40

42 Energy Savings Opportunities Estimated annual energy dollars saved for implementing off-hours airflow reduction in one OR, based on: Chicago weather; $0.11/kWh for electricity and $0.65/therm for gas 13 unoccupied hours per day Recirculating air handling unit 10 ORs annual savings is $20,000 to $32,000 41

43 Energy Savings Opportunities If the OR is served by a 100% outside air unit, savings increase. Chicago weather; $0.11/kWh for electricity and $0.65/therm for gas 13 unoccupied hours per day 100% OA air handling unit 10 ORs annual savings is $27,000 to $57,000 42

44 General Design Approach Terminal unit and reheat coil on supply Supply box maintains constant required airflow Reheat coil valve modulates to control temperature Return box maintains pressurization Supply terminal unit Corridor OR Sterile Core 43 Return box

45 Occupied/Unoccupied Operating Rooms Sequences of Operations Case Studies All of these examples have ROBUST building automation systems. This is a must have before attempting implementing an unoccupied mode for ORs ORs MUST be positively pressurized at ALL times!! 44

46 Case Study 3 Unoccupied Mode for 12 ORs Four Operating Room AHUs each serving three ORs (12 total) Each AHU has supply and return fans with VFDs 45

47 Case Study 3 Unoccupied Mode for 12 ORs 46 Most OR s can be positively pressurized with six to eight air changes per hour; let temperature float during unoccupied mode with deadband

48 Case Study 3 Unoccupied Mode for ORs 1 though 6 47 Hospital with Level 1 Trauma Center. Four ORs were decided to be left occupied all the time: ORs 1,2, 11 and 12 (also the biggest)

49 Case Study 3 Unoccupied Mode for ORs 7 though California Mechanical Code allows a MINIMUM of 6 ACH; it is not recommended or typically feasible to go below this

50 Case Study 3 Unoccupied Mode BEFORE Changes 49

51 Case Study 3 Unoccupied Mode AFTER Changes 50

52 Case Study 3 Unoccupied Mode AFTER Changes Date/Time AH.D416.SPRES.SP Static Pressure Setpoint "w.g. AH.D416.SPRES Actual Static Pressure "w.g. AH.D416.SVFD Supply Fan VFD % Speed 2/8/2012 7: /8/2012 6: /8/2012 6: /8/2012 5: /8/2012 5: /8/2012 4: /8/2012 4: /8/2012 3: /8/2012 3: /8/2012 2: /8/2012 2: /8/2012 1: /8/2012 1: /8/2012 0: /8/ /7/ : /7/ : UNOCCUPIED TIME PERIOD 51 Different fan than previous screen shots

53 Case Study 3 Unoccupied Mode AFTER Changes Supply Fan Speed % D41.6 Supply Fan Operation Before Implementation Static Pressure (in WC) Supply Fan Speed % Static Pressure (in WC) 10 0 After Implementation AH.D416.SVFD AH.D416.SPRES.SP AH.D416.SPRES

54 Case Study 4 Dual Supply and Return VAV boxes Supply 2500 cfm Return 1914 cfm Offset 586 cfm OR Pressure RECOMMENDATION Add door switches which deactivate the BAS room pressure alarm when an OR door is open 53

55 Occupied/Unoccupied Schedule 54

56 General Instructions for RE-activating an OR by Overriding Unoccupied Mode Provide in-service training to the clinical staff 55

57 General Design: Return Damper vs. VAV Box? IT MAKES A DIFFERENCE! Return dampers don t provide tight control over space pressure 56

58 DESIGN Example Good start to the sequence in design is important. This sequence does not include a time of day schedule, so the OR could go unoccupied in the middle of the day if there is no motion for 15 minutes: probably not desired

59 Mode Control Methodology How And When To Use Occupancy Sensors, And The Downfall... Does the Motion Detector have Pass Through Mode? 58 Problem: If occupancy sensors are used to trigger the room to go back occupied, they can and will have false activation for OR cleaning, resupply of sterile instruments, general preparation, and CUT THROUGH

60 Mode Control Methodology Ideal Solution for ORs Inside the OR 59 Motion Detector is ONLY used to provide the BAS with an unoccupied signal after the schedule has dictated the OR can go unoccupied. The MD prevents the OR from going unoccupied if the room is in use. Display inside OR provides critical information to staff

61 Mode Control Methodology Ideal Solution for ORs Outside the OR MANUAL intervention is required by the CLINICAL staff to force an OR back into occupied mode during the unoccupied time period OR Monitor OUTSIDE the OR indicates what state the room is in OCCUPIED or UNOCCUPIED and can be used to activate an OR 60

62 Ideal Solution for ORs Occupied/Unoccupied Mode Nurse s Station Recommended that the Nurse s Station be provided with a way to view the status of ORs IF they will be changing state 61

63 Ideal Solution for ORs Occupied/Unoccupied Mode Nurse s Station 62 New products provide capability to monitor, schedule and change the status of an OR remotely from the Nurse s Station

64 Building Pressurization International Energy Conservation Code Chapter 4 Commercial Energy Efficiency Section C402 Building Envelope Requirements C Building Test. The completed building shall be tested and the air leakage rate of the building envelope shall not exceed 0.40 cfm/ft 2 at a pressure differential of 0.3 inches water gauge (2.0 L/s m 2 at 75 Pa) in accordance with ASTM E 779 or an equivalent method approved by the code official

65 Building Pressurization Case Study 5 64 Tested and found much better than code 0.14 CFM/Sq.Ft.

66 Building Pressurization Case Study 5 65 Building Pressurization Offset 5-10% typical This building = 8% 65

67 Building Pressurization Case Study 6 Building Pressure Sensor 66

68 Building Pressurization Case Study 6 Supply cfm = 30,300 Min OA = 7,575 Fixed Exhaust = 910 cfm Building Pressurization = 10% (of supply fan cfm) = 3,030 Return fan cfm setpoint = 30, ,030 = 26,360 Recirculation Air = Supply cfm OA flow = 30,300 7,575 = 22,725 DON T LINK DAMPERS NO AFMS ON ECON OA Unit Exhaust Air = Return Air Recirculation Air = 26,360 22,725 = 3,635 ECON Damper position may not be equal to Exhaust Damper position!! PROBLEM NOT ALL OA IS MEASURED 67 PROBLEM BALANCING MATRIX DID NOT LEAVE ANY AIR FOR BUILDING PRESSURIZATION 67 67

69 Summary Codes and ACHs ORs are allowed to have an unoccupied mode PROVIDED they remain positively pressurized OR Room Pressure Minimum wg Typically control to or greater Air Changes per Hour 15 per IDPH 20 per ASHRAE 30 typical at many facilities 8 ACH in unoccupied mode (6 ACH minimum). (Verify this holds room positively pressurized) 68

70 Summary Design Approach Design Include supply and return terminal boxes, or, better yet, air valves, not just dampers Include occupancy sensors with multiple technology, and pass-through mode capability Include door switches Provide clear indication of room conditions and occupied/unoccupied mode status both inside and outside of OR Provide remote monitoring and control from nurse s station 69

71 Summary Sequence of Operations Best Sequence Uses a schedule PLUS occupancy sensors to initiate unoccupied mode Uses manual intervention to re-occupy if an OR is needed during unoccupied time Temperature and Humidity Allow float (deadband) in the OR temperature during unoccupied mode Maintain OR humidity Testing and Trending! Test/calibrate all BAS sensors and verify room pressure Trend ORs, room pressure and mode 70

72 Summary Adding Unoccupied Mode Chose ORs with terminal boxes on supply AND return Can work with return damper control, but test Be careful of constant volume systems will only work if fan tracking is utilized, and even then, seldom works properly. The problem is on the return side. 71

73 AND don t forget to look at your OR fans once in a while... 72

74 Thank You John D. Villani, P.E. Vice President, Grumman/Butkus Associates, Illinois , Laurence Steiner, P.E. Associate Vice President, Grumman/Butkus Associates, Wisconsin , 73