Date: Tue, 25 Sep 2007 10:43:03 -0700
Reply-To: Gordon Miller <miller22**At_Symbol_Here**LLNL.GOV>
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From: Gordon Miller <miller22**At_Symbol_Here**LLNL.GOV>
Subject: Problems with HEPA-Filtered Vacuum Cleaners

Lessons Learned about problems with HEPA-filtered vacuums follow. One 
addresses the popular Nilfisk GM80, the other 15-gallon Pullman-Holt 
machines. "RCT" is Radiation Control Technician.

First, Nilfisk:

Nilfisk GS625 Vacuum HEPA Filter Failure

Lesson ID: 2007-SR-WSRC-0021 (Source: User Submitted)

Originator: Washington Savannah River Company

Date: 9/18/2007  Contact: WSRC SDD RCO Manager - Gary 
Chandler(803)725-1325, gary.chandler**At_Symbol_Here**

Classifier: Rod Hutto   Reviewer: ADC

Statement: When using Vendor supplied equipment to complete tasks 
that are not typical, be aware that the vendor supplied documentation 
may not adequately address the equipment requirements and/or the 
precautions for effectively handling the task to prevent exceeding 
equipment limitations.

There are various portable HEPA vacuum systems in use at SRS 
facilities. These vacuums are relied upon to protect workers from 
airborne constituents and to help prevent the spread of 
contamination. Although vendor information may prescribe system 
equipment and operations requirements in general terms for these 
units, some operations and materials may not have been accounted for 
in the manufacturer-supplied documentation.

In this case, use of the incorrect type of main filter and absence of 
the micro filter contributed to failure of the HEPA filter. The 
manufacturer "Instructions for Use" did not identify the nonstandard 
main filter and micro filter required when collecting abrasive materials.

Discussion: On 8/14/07 a HEPA vacuum was being used as a point source 
exhaust for drilling concrete samples on top of a sump cover in a 
contamination area. Work was being conducted outside and workers were 
in one pair of Anti-Cs and a face shield. Personal air samplers (PAS) 
were being worn by the workers and an exhaust air sampler was 
sampling the HEPA vacuum exhaust. At 1110, a Radiological Control 
Inspector (RCI) responded to indications of dust coming from the 
front filter of a dual-filtered HEPA on the vacuum.

Upon follow-up vacuum inspections, it was noted that concrete dust 
had exhausted from the HEPA filter. When the vacuum motor was 
disassembled, it was determined that the motor-to-HEPA filter seal 
was intact (See Attachment 1, Figure 1). The vacuum bag inside the 
unit had broken (See Attachment 1, Figure 2) and the concrete debris 
had also broken through the vacuum main inner cloth filter (See 
Attachment 1, Figure 3). The breakdown of these two inner barriers 
caused the vacuum motor to exhaust concrete dust directly to the HEPA filter.

Cloth Micro-Filter Importance:

The cloth micro-filter is the last stage of filtration to provide 
additional protection to the motor and HEPA filter, but was not 
installed. It can be assumed that the cloth micro filter would not 
have prevented failure of the HEPA filter since the cloth main filter 
degraded. Per communication with Nilfisk, poly composite main filter 
and micro filters should have been used.

Analysis: Immediate Actions and Follow-up Actions:

The HEPA vacuum was secured and the work was stopped. All workers 
exited the job site. No detectable contamination was found on 
personnel or personal effects or within the general work area. 
Management notifications were made and follow-up actions were 
initiated. The vacuum was bagged and transferred to a containment hut 
pending dismantlement and further investigation.

Additional corrective actions following the investigation included 
the identification and tagging out of other available units within 
the organization, ordering more robust replacement filter materials 
for the units based on the constituents being controlled, upgrading 
storage requirements for the units, and issuing lessons learned 
information to group and site personnel.

SRS ALARA Center Follow-Up Actions:

On 08/22/07, the SRS ALARA Center issued an email to WSRC 
Radiological Protection Area And Facility Managers that included 
actions for them to take and also included the following additional 
-The Nilfisk GM80 series HEPA vacuum is the same technology as the 
GM/GS625 and the same recommendations apply.
- Nilfisk will revise the GM80 and GM/GS625 "Instructions for Use" to 
add a caution documenting when to use the poly composite filters. 
This revision is being made immediately for SRS but a company global 
change will take approximately six months. Any DOE site wanting to 
make the revision immediate must contact their Nilfisk district manager.
- All future Nilfisk GM80 and GM/GS625 vacuums supplied to SRS will 
come with poly composite filters.

Actions: WSRC-Specific Recommendations:

HEPA Filter Custodians should ensure that Nilfisk GM/GS625 main 
filter and micro filters are inspected to verify integrity. These 
filters should be replaced with poly composite filters if the 
possibility exists to vacuum abrasive debris such as concrete. The 
poly composite main filter and micro filter will be the standard 
filters provided by Nilfisk when the GM/GS625 and GM80 HEPA vacuums 
are ordered by SRS in the future.
The AES poly composite main filter is part number 1723200. The AES 
poly composite micro filter is part number 1723000.
The Nilfisk GM80 series HEPA vacuum uses the same micro filter as the 
GM/GS625 and the part number for the GM80 poly composite main filter 
is 01723110.

Organization/Project Operating Experience Program Coordinators should 
share this information with their Project Area Personnel involved in 
like and similar activities, including:
Radiological Protection Personnel
Others as applicable

Next Pullman-Holt:

Breach in Pullman-Holt 15-Gallon HEPA Vacuum Filters

Lesson ID: RCCC-07-014 (Source: User Submitted)

Originator: River Corridor Closure Contractor, Safety and Health Organization

Date: 9/20/2007  Contact: Robert Brounstein, (509) 372-9145

Classifier: N/A   Reviewer: N/A

Statement: For all portable HEPA vacuum cleaners prior to use:

Ensure that the portable HEPA vacuum cleaner is on approved use list
Ensure Vent and Balance seals are in place and current
The current single inspection process of the filter system increases 
the workers opportunity for exposure due to possible equipment failure.

Discussion: After asbestos removal activities in 109N, workers were 
using a Pullman-Holt HEPA vacuum cleaner (15gal.) to clean up 
asbestos inside the containment area. A Laborer from PAS (an asbestos 
abatement subcontractor for Washington Closure Hanford) observed 
visible emissions coming from the exhaust of the vacuum cleaner. The 
workers personal protective equipment (PPE) included air purifying 
respirators and powered air purifying respirators. The vacuum was 
shut down and taken out of service. Area air monitors and individual 
lapel monitors indicated no airborne asbestos concentrations above 
action limits.

Analysis: On Tuesday morning, August 14, 2007, following the Plan of 
the Day (POD) meeting, the work crew worked for several hours inside 
the Containment Area when visible emissions were noticed coming out 
of the exhaust port of the vacuum. The vacuum was immediately shutoff 
and the equipment and area was put in a safe condition. WCH 
management was notified and all like vacuums were temporarily isolated.

On Thursday, August 16, 2007, the Vent and Balance seals were broken 
on the suspect HEPA vacuum cleaner and the HEPA filter was inspected. 
The inspection revealed that double sided tape had failed to keep the 
filter box attached to the upper housing unit of the vacuum. It was 
also discovered that the filter box had fallen into the debris 
holding container, which allowed vacuumed material to exit the exhaust port.

As a result of this discovery, PAS inspected the remaining four 15 
gallon vacuum cleaners and six 5 gallon vacuums. It was discovered 
that three out of five 15 gallon vacuum cleaners were compromised. 
The double sided taped had failed and the filter boxes had separated 
from the upper housing unit. One of the vacuums was missing the 
filter pr-screen on the HEPA filter. All six 5 gallon vacuums were 
determined to be in good condition.

Additional inspections were conducted on some brand new, 15 gallon 
(still in the box) vacuum cleaners from the same vendor. It was 
discovered the double sided tape had also failed. All suspect HEPA 
vacuum cleaners were taken out of service and tagged Do Not Operate.

During the critique, it was noted that the PullmanHolt vacuums needed 
to be delivered to Fluor Hanfords Vent and Balance group. This group 
is responsible for the DOP test, which certifies the HEPA vacuums for 
service. Upon successful completion of the DOP test the vacuum is 
closed and a seal is placed on it. The vacuums are sealed so that 
opening the vacuum to conduct normal inspections and bag change outs 
would render the DOP certification invalid.

The suspect HEPA vacuums were considered a Single Use item. Once they 
have been filled up they were disposed of properly.

(the original lessons learned document, with pictures, can be viewed 

Actions: When these issues were identified, the work crew and WCH 
management implemented corrective actions to address and correct the 

The immediate actions taken upon discover were:

the suspect vacuum cleaner and work location was isolated and placed 
in a safe condition a notice was sent out to the management team 
about the event RCTs conducted surveys of the areas in and around the 
Containment Area for spread of any type of contamination the suspect 
and all like vacuum cleaners were decontaminated, surveyed and 
inspected all suspect HEPA vacuum cleaners were taken out of service 
and tagged Do Not Operate The follow-up actions taken to close the issue were:

New heat wielded HEPA filter boxes were ordered and are currently in use

Workers need to be informed about the changes in the DOP 
certification seal that would allow workers to open the vacuum 
container for inspection and bag change out

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