international standards in comparison

Weiss Klimatechnik GmbHInternational Hygienic Standards

MEDICLEAN®

Christoph Löhner


MEDICLEAN®

Christoph Löhner

Clean Enviroment in the Industry to prevent contamination of the product


MEDICLEAN®

Christoph Löhner

Clean Enviroment in the Operating theatre to prevent an Infection of the patient

Weiss Klimatechnik GmbHLidwell-Study ( Correlation of CFU and Infection rate)

- 7500 surgeries - 19 Hospitals- 5 ½ years- Finished in 1980

Weiss Klimatechnik GmbH

100%

21%16%

21%

42%

0%

20%

40%

60%

80%

100%

Distribution hospital infection

total

others

infected wound

acute respiratorydisease

urinary tract infection

Frequency of Infections in Germany


95%

5%

0%

20%

40%

60%

80%

100%

operativ postoperativ

Surgical hospital infection



15

10

1

02468

10121416

1

days

Extension of hospital treatment though infection

infected wound





711

618

126

0

100

200

300

400

500

600

700

800

1

Cost through hospital infection in Mio. Euro

infected wound





Tasks of Hygienic Air Conditioning:

• Prevention of Air Born Infections during Surgery

• Management of thermal loads

• Reduction of content of harmful narcotic gases

• Maintenance of a comfortable climate in the OT

6

Weiss Klimatechnik GmbHTable of Various Standards and Design Indices

Room Class I(a)German DIN

Dec. 2008Russian GOST RSince 21.04.2006

Size of Laminar Flow Ceiling

3,2 x 3,2 m Min. 9 m2

Recirculation ?Fresh Air Amount

Yes (1.200 m3/h Fresh Air)

Yes(min. 100 m³/h x person)

Supply air velocityTotal Air Volume

≥ 0,23 m/s, 8.800 m³/h

0,24 – 0,3 m/s9.000-11.000 m³/h

Overflow into adjoining rooms ?

Yes, no figure Yes, no figure

Air Curtain 2,0 m above floor level

2,1 m above floor level

Three stage supply air filtration

Min F5 + F9 + H13 F7 + F9 + H14

Sound pressure level ≤ 48 dB (A) Not specified

Acceptance Test Rate of Turbulence Or Measurements by protection degree

Clean Room Class ISO 5/6

English HTM 03-01Since 2007

2,8 m x 2,8 m Rec 3,2 m x 3,2 m

Yes(AC/hr 25, min.2700 m³/h fresh air)

0,38 m/s on 2 m height11.900 m³/h

Yes, no figure (close to ceiling recommended)

2 m above floor level

G3 + min. F9 + min. H 10

≤ 55 dB (A)

Velocity/Validation

Weiss Klimatechnik GmbHDesigning - Main Topics

Room Class I(a)German DIN

Dec. 2008ASHRAE

2007

Size of Air Diffusor 3,2 x 3,2 m2 No information(laminar airflow “interest”)

Recirculation ? Yes (1.200 m3/h)Fresh air

Yes(20 AC/hr)Fresh air 4 AC/hr

Supply air velocityTotal Air Volume

≥ 0,23 m/s, 8.800 m³/h

Not specified2.000-2.700 m³/h depending on size of OT

Overflow into adjoining rooms ?

Yes, no figure Yes, with pressure monitoring

Air Curtain 2,0 m above floor level

Not specified

Three stage supply air filtration

Min F5 + F9 + H13 2 Filters (8, 17)(2 could be HEPA filter)

Sound pressure level ≤ 48 dB (A) Not specified

Acceptance Test Rate of Turbulence Or Measurements by protection degree

Weiss Klimatechnik GmbHDIN 1946-4 (German Standard)

General Design Criteria for OR Class 1AOperating Rooms Class1 A are for Orthopaedic, Cardiac,Neurosurgery,Transplant Surgery RoomsMinimum Size of OR 45 m²Height requirements (Clear Height FFL) 3,5 m Minimum size of a Laminar Flow Ceiling 3.2 x 3.2 mPartial walls or Curtains around the LF down to 2,1 m Temperature 19 – 26°CHumidity 35 – 60% r.h.Noise Level in the OR 48 db(A)Exhaust Air should be extracted homogenously from the roomAir Volume is defined by Downflow velocity below the LF Velocity 0.24 m/s average = 8.800 m3/h

Weiss Klimatechnik GmbHDesign indices

air supply between difference etemperatur t Q

[kJ/kgK] 1,0 air ofheat specificc 8.850

Q

][kg/m 1,2 air of density 8.850Q

[kW] load cooling Q t cVQ

/h][mflow air V 3,2mm3V

3

3

Δ 3

3600

112,1

ς 112,1

Δς

3600/24,02,

kW

sm

Calculation of air flow for removal head load

∆ t Cooling load (kW)

0,5 1,5

1 3,0

1,5 4,5

2 6,0


Requirements of the DIN 1946-4; December 2008

Building elements “RLT units for OT departments” shall be preferably installed on the floor directly above or close by.

Design Advice according DIN 1946-4


Advantage:

- Service and Maintenance outside OT

- Better Control of the Sound level

- Better mixing possibilities of fresh air and return air

Disadvantage:

-Required space for duct system

-Requires a large technical room

Air Conditioning Concept acc. DIN 1946-4(Remote plant system acc. HTM 03-01)

„Ideal solution – from technical-hygienic view“


Circulating Air Modules for Suspended Ceilings , Type ULA

Alternative System acc. DIN 1946-4(Modular System acc. HTM 03-01)


Advantages:- No requirement for large technical room for AHU`s- low space and room requirements for ducts- low operating costs

Disadvantages:- Reduced possibilities of mixing of circulating air with supply air- Reduced possibilities of sound absorption by very short air distances

Ceiling-suspended circulating air modulesAlternative System acc. DIN 1946-4

Weiss Klimatechnik GmbHAlternative Solution with Wall reciruclating modulesinstead of ceiling suspended modules


Circulating air wall module

Possibilities of installation:- Inside the OT- Directly outside the OT- Integral component in a wall

Alternative Solution with Wall reciruclating modulesinstead of ceiling suspended modules


Plant scheme Mediclean 120.3 DXU

FFA 32/32

Weiss Klimatechnik GmbHOperating Room Class 1 A


Operating Room Class 1 AMedia Supply Bridges (MVB)

Weiss Klimatechnik GmbHAlternative- Solution to normal Pendents:


Advantages with an example:

- Inspection possible from adjoining room

- Integral component of a wall

Circulating air wall module

Operating Room 1 A with Wall Recirculating Module

Weiss Klimatechnik GmbHNew HTM 03-01 (British Standard)

General Design Criteria for UCVUCV (Ultra clean ventilation) Theatres for Orthopaedic, CardiacTransplant, NeurosurgeryMinimum Size of OR 55 m²Minimum Clear Room Height 3,5 m ( better 3,8 m)Minimum size of a UCV Canopy 2.8 x 2.8 mor 3.2 x 3.2 m in case of bigger OR`s(Distance between UCVCeiling and perimeterial wall minimum 1 m)Partial walls around the UCV down to 2 m Temperature 19 – 23°CHumidity 35 – 60% r.h.Noise Level in the OR 55 db(A)Exhaust Air via Pressure Relief Dampers to the adjoining Rooms (normally no exhaust air in the OR)Air Volume is defined by Downflow velocity over the UCV At 2 metres 0.38 m/s average = 11.900 m3/h


Typical HTM03-01 Layout

Weiss Klimatechnik GmbHTypical Plant design acc.HTM03-01for Modular Plant System


Typical UCV Operating Room

Partial Walls

Recirculation Module



Pressure Relief Damper


Main Design Mistakes

1. The design of the Air Flow is done according Ashrae and does not match the requirements for a Laminar Flow Ceiling

Example: Operating room with the dimensions 5 x 6 meters and an internal room height of 3 meters would require according American ASHRAE 20 Air changes per hour which would result in a total Air Volume of 1.800 m³/h

A Laminar flow Ceiling with the dimensions 3 x 3 meters would require a minimum Air Flow Volume of 7.776 m3/h

Size of ceiling x 0,24 Velocity (m/s) x 3.600 seconds = m³/h

Ceiling (3 x 3 m) =9 m² x 0,24 m/s x 3.600= 7.776 m³/h


Main Design Mistakes

2. The design of the Room temperature and the Supply Air temperature is not matching because the Air Flow is not sufficient to provide a drought free enviroment when you have internal heat loads (light, monitors,staff)

Example: Operating room with an Internal heat load of 3,0 KW and a total Air Volume of 1.800 m³/h would mean keeping a room temperature of 20°C the supply air temperature has to be 15°C (∆ t = 5 K)

Consequences: In a combination with a Laminar Flow Ceiling this will lead to droughts and turbulences as well as to a reduction of the clean area at the height of the Operating table


MEDICLEAN®

Summary

1. Detailed knowledge of standards is important.

2. It will be profitable to include hygienists in due time.

3. Increasing requirements at operating theatres shall be considered duly.

4. Integrated strategy of architecture, room air technology, medicine technology and lighting

5. Highest possible safety for the hygiene acceptance

international standards in comparison

Health & Medicine