Steam audit Example.pdf

Subject: VA Steam Audit

This letter is to summarize the steam system evaluation done at subject facility last. Report with pictures and explanations follow.

There were several items that need attention. They are:

Boiler Plant

1. Replace boiler header traps and boiler room pit traps (4 total). All were plugged / cold.

2. Add boiler header trap to temporary boiler trap connection. Connection is there, just no trap was installed.

3. Boiler blowdown –, measure and document surface blowdown conductivity daily, and adjust as needed to stay below 3000 mmhos, and PAlk levels below 600.

4. Re-start DA Tank steam heat control valve.

Sterile Processing

1. Insulate sterilizer inlet piping and PRV station piping (next to steam filters).

2. Change out or clean sterilizer steam filters quarterly and document. (The Steris filters are sintered metal and can be cleaned in the ultrasonic and re-used). It appears they have never ben serviced.

3. Replace all steam filter traps (5 traps).

4. We replaced the pressure gage and re-set the pressure regulator serving the sterilizers to

60 psi. We then tested with 2 sterilizers running (empty chambers) and the pressure held above 56 psi.

We can have a conference call to discuss or review.

Respectfully submitted, Attachments:

Steam Audit Report Steam Quality Test Results, and Calculation Explanation

Steam Audit Report Location: Alexandria VA Medical Center, Pineville, LA - Dates:

Situation Evaluate and recommend repairs to steam and sterilizer piping between boiler plant and Building 7 where sterilizers are installed. Steam pressure alarms are indication the pressure is dropping below 50 psi, the minimum required by Steris.

Background There are Steris sterilizers Century Series V148H’s and V120. They were running on 50 psi steam, generated the facility boiler plant’s temporary boiler.

Findings and Recommendations LEFT HAND Analysis The LEFT HAND analysis is a way we break down the steam system into component parts. Each has specific components that impact sterilizer operation and steam quality. Like the fingers on the left hand, they all work together:

The THUMB is the large piping from the Boiler Room The high pressure distribution piping up to the PRV station is the INDEX finger.

The MIDDLE finger is the long run of intermediate (usually 50-60 psi) pressure piping.

The RING finger represents the crucial piping that is "married" to the sterilizer.

The LITTLE finger is the condensate piping and practices in the CS department.

BOILER ROOM

The blowdown schedule is being followed.

TDS and pH measurement (Data Sheet) Pressure does not drop suddenly, even if only slightly.

Header-piping drip legs are full-sized.

Traps are on and hot.

Operation was tested.

HIGH PRESSURE SUPPLY LINE TO PRV

Insulation is in good condition.

Drip stations are located every 300 ft along the main.

Drip stations are located at low points.

Drip stations are located ahead of valves that may close automatically.

Drain legs are large enough.

Traps are on and hot. (Data Sheet) Traps are not overloaded.

MEDIUM PRESSURE RUN OUT TO SPD

Insulation is in good condition.

Drip stations are located every 300 ft along the main.

Drip stations are located at low points.

Drip stations are located ahead of valves that may close automatically.

Drain legs are large enough.

Traps are on and hot. (Data Sheet) Traps are not overloaded.

STERILIZER ROOM PIPING

Insulation is in good condition.

Drip stations are located AT END of the main.

Drip stations are located at low points.

Drip stations are located ahead of valves that may close automatically.

Drain legs are large enough.

Traps are on and hot. (Data sheet) Traps are not overloaded.

Filter change out.

CONDENSATE PIPING AND STERILIZER OPS

Lifting is not excessive.

Water is hot and pumping.

Insulation is in good condition.

Drip stations are located at low points.

Drip stations are located ahead of valves that may close automatically.

Drain legs are large enough.

Traps are on and hot. (Data sheet) Traps are not overloaded.

Tape of sterilizer operation (Copies of cycle sheets)

Report Findings Nomenclature – Every topic in the following section represents a key factor in delivering “good” steam from the system.

The note “OK” after the topic means it was inspected and verified. “NOK” means “Not okay”, and there is an issue, and corrective action should be considered. We always follow a “NOK” with specifics and recommendations.

BOILER ROOM

The blowdown schedule is being followed. OK Bottom blowdowns are being done twice daily.

TDS and pH measurement NOK – Boiler conductivity (solids content) is being measured daily by plant operators, but conductivity has exceeded 4000 mmhos. Here is a picture of the daily log:

Measure and document surface blowdown conductivity daily, and adjust as needed to stay below 3000 mmhos every day. Uncontrollled solids can lead to foaming and carryover of boiler water into the steam distribution piping.

Our recommended target concentration of solids is < 3000 mmhos and PAlk below 600. When too many minerals (especially alkaline minerals) are dissolved in boiler water, it can foam… just like making spaghetti at home. The solids in the boiler get carried out into the system, can stain sterilized items, create wet loads, and can plug small orifices (like in traps). See next page.

Per Cleaver Brooks (the boiler manufacturer): Solids, such as sodium salts and suspended dirt, do not readily form scale. However, as boiler water boils, forming relatively pure steam, the remaining water becomes increasingly thicker with solids. If the concentration is permitted to accumulate, foaming and priming will occur, and the sludge can cause harmful deposits … Therefore, lowering or removing concentrated solids requires the use of boiler water blowdown.

We believe the high solids concentration has plugged all the boiler plant traps (see below).

Pressure does not drop suddenly, even if only slightly. OK Header-piping drip legs are full-sized. OK

Here is the relationship of the header and trap to the boiler. All boilers “throw” some water, but as described above, too many solids causes the boiler to throw lots of water, and the water is full of solids, so the traps get plugged!

Here is how multiple boilers are piped in relation to the header:

The header acts as a separator and the traps drain the water away… but when the traps are plugged, the header fills with water, creating wet steam and high pressure drops.

Boiler

Header

Drip Leg Trap

Traps are on and hot. NOK Replace boiler header trap. The existing trap is well piped, and the drip leg is proper:

Boiler header drip leg Boiler header trap

The trap has a problem, it is plugged, it should read 270F or higher:

These traps are in the pit where steam flows out into the building. The pit is partially flooded, so that is the reflection in this picture of the windows above. These traps are also plugged.

Here is the piping from the temporary boiler. You can see the drip leg and trap connection, but no trap.

In summary, since the steam was a suspected source of pressure drop, we need to place emphasis on two areas: blowdown and header drainage. Without proper blowdown, solids will leave the boiler. Normally, the header catches and drains this mineral laden water, but without proper trapping, we can’t drain the header.

HIGH PRESSURE SUPPLY LINE TO PRV

Insulation is in good condition. OK Drip stations are located every 300 ft along the main. OK Drip stations are located at low points. OK

Here is the trap in the sub-basement below sterile processing. It is OK.

Drip stations are located ahead of valves that may close automatically.

Drain legs are large enough.

Traps are on and hot. (Data Sheet) Traps are not overloaded.

MEDIUM PRESSURE RUN OUT TO SPD

Insulation is in good condition. NOK See picture below:

This needs to be cleaned up and re-insulated.

Drip stations are located every 300 ft along the main. OK Drip stations are located at low points. OK Drip stations are located ahead of valves that may close automatically. OK Drain legs are large enough. OK Traps are on and hot. OK Traps are not overloaded. OK

STERILIZER ROOM PIPING

Insulation is in good condition. NOK Insulation around the filters needs to be replaced/installed.

Steris sells re-usable filter insulation :

All 5 filter traps are blowing / leaking steam. This style of trap is susceptible to solids, except instead of plugging, the solids cause them to leak.

These are plastic bags with replacement filter elements (still good).

In addition there are no records of filter element change out - Change out sterilizer steam filters quarterly and document. (The Steris filters are sintered metal and can be cleaned in the ultrasonic and re-used).

Drip stations are located AT END of the main. NOK see below:

This is the end of main trap between the sterilizers and washers, it is also leaking steam. The meter shown is an ultrasonic stethoscope which shows steam flow. Replace the trap.

So, these leaking traps may be the source of the steam vent flow above the loading dock:

Drip stations are located at low points. OK Drip stations are located ahead of valves that may close automatically. OK Drain legs are large enough. OK Traps are on and hot. OK Traps are not overloaded. OK Steam Quality NOK– We did 3 tests. The sterilizer steam quality tested at not acceptable dryness (according to AAMI/ANSI ST-79 standard "Comprehensive guide to steam sterilization and sterility assurance in health care facilities") with dryness below 97-100%. The tests were 95.8%, 95.2% and 95.3%. (See test data sheet and explanation attached). We believe that fixing the boiler plant trap situation will remedy this.

Air venting adequate OK

CONDENSATE PIPING AND STERILIZER OPS

Lifting is not excessive. OK Water is hot and pumping. OK Insulation is in good condition. OK Drip stations are located at low points. OK Drip stations are located ahead of valves that may close automatically. OK Drain legs are large enough. OK Traps are on and hot. OK Traps are not overloaded. OK We replaced the pressure gage and re-set the pressure regulator serving the sterilizers to 60 psi.

We then tested with 2 sterilizers running (empty chambers) and the pressure held above 56 psi.

New gage on sterilizer steam feed.

CONCLUSION:

Records and Communication: Steam loads change hourly with the type of system you have installed. The kitchen, domestic water heating, and building heat loads can create big changes in the steam demand. All these external physical factors can impact wet steam and create wet loads… So, good documentation and communication will help diagnose any future pressure drop occurrences.

8/6/20 Page 1 Moisture in Dead Weight Calorimeter Calculation Steam Sample from House Steam Measurements taken XXXXXX Location Sterilizer 1 Steris Strainer Blowdown

Test 1 - 3 Steam quality dryness fraction test calculation

Mb 1.955 1.955 1.955 lbs Weight of container dry Mbw 14.060 11.145 12.225 lbs Weight of original container and water Mw 12.105 9.190 10.270 lbs Weight of water only T0 73.6 81.1 81.8 F Temperature of water beginning T1 140.6 142.5 140.9 F Temperature of water ending Me 14.845 11.695 12.815 lbs Weight of ending container and water Mc 0.785 0.55 0.59 lbs Weight of ending minus beginning P 60 60 60 psig Steam pressure Ts 307.61 307.61 307.61 F Steam temperature (compensate for altitude) S 277.6 277.6 277.6 Btu/lb Sensible Heat L 904.3 904.3 904.3 Btu/lb Latent Heat

SQ 0.958 0.952 0.953 % Steam Quality (Dryness Value)

St 79 97% 97% 97% Jul-20 96% 95% 95%

1 2 3

92.0%

93.0%

94.0%

95.0%

96.0%

97.0%

98.0%

99.0%

100.0%

1 2 3

Pe rc en ta ge M oi st ur e

Sample Number

Steam Dryness

St 79

Jul-20

Steam Quality (Dryness Fraction) Calculations

Adapted from Association for the Advancement of Medical Instrumentation

(AAMI) second edition of ANSI/AAMI ST79, Comprehensive guide to steam sterilization and sterility assurance in health care facilities (2010), and European

Standard EN285 and British Standard HTM-2010

Derivation of the steam quality (dryness fraction) value equation

1.1 The equation for the steam dryness fraction value can be derived as follows.

1.2 Steam supplied from the main will contain dry steam with a small amount of moisture carried as droplets in suspension at the same temperature.

The dryness fraction, D, is defined as:

D = Mdry / Msteam = Mdry / (Mdry + Mwet)

(Equation-1) where a given mass Msteam of steam contains a mass Mdry of pure dry steam and

Mwet of moisture. Dry saturated steam has a dryness fraction of 1.0.

1.3 If dry saturated steam is allowed to condense in cold water, then the temperature rise of the water is related to the amount of latent heat given up by the condensing steam. If the steam contains moisture, then the latent heat (and the temperature rise) will be less than for the same mass of pure dry saturated steam. The dryness fraction may then be estimated (the estimate being known as the dryness fraction) by equating the heat gained by the water to the heat lost by the steam.

1.4 At the start of the test the container holds a mass Mw of water at a temperature of T0 . At the end of the test the temperature has risen to T1, Heat gained by water = (T1 – T0)cMw

(Equation-2) where c is the specific heat capacity of water at a representative temperature between

T0 and T1 (at 70F, c = 1.0).1.5 The heat lost by the steam is equal to the latent heat of vaporization plus the heat lost from the condensate and moisture as they cool from

Ts to T1 .

Heat lost by Steam = LMdry + (Ts – T1)cMc = DLMc + (Ts – T1)cMc

(Equation-3) where L is the specific latent heat of vaporization of steam at temperature Ts and Mc =

Msteam is the mass of condensate and moisture. Equating (Equation-2) and

(Equation-3) and solving for D gives:

(Equation-4) where the term A represents the effective heat capacity of the container and other piping. The rubber or copper pipe is not included as it is assumed to be at steam temperature at the start of the test. The heating factor estimates how much heat is absorbed when the component is heated from T0 to T1 during the test. Plastic containers near room temperature can effectively be ignored, making A = 0.

1.6 Example calculation: In a dryness value test the temperature of the water in the container rises from T0 = 48F to T1 = 93F. The average steam temperature during this time is Ts = 307F. The initial mass of water in the container is Mw = 24 lbs, and the mass of condensate is Mc = 1 lbs.

From tables, c = 1.0, and L = 904.3 Btu/lbs. Then, using Equation-4:

D = (93 – 48) (1 x 24 +0) / (904.3 x 1) – (307 - 93)1/904.3

D = 95.8%