Aspe nat'l convention let civildsncontmtsys slideshare

Randy Holland, MBA
Best Practices & Public Policy Consultant
Let the Civil Designer Deal with the
Containment Backflow System

Backflow Prevention: 2 doctrines
Introduction
Isolation:
Plumbing code enforcement
•asserts that ‘we can take care of any cross
connection contamination risks by enforcing the
plumbing code’. Simple as that.
Containment:
Protection against unknown changes
•Argues no, that’s not good enough because of
unknown changes to individual plumbing systems
after the C of O is issued.

The water engineering community has been struggling with new
professional liability risk involving the location of premise isolation backflow
preventer systems; Not because of new design practices, but because of
new information about the old practices. There has been a slow trickle of
warnings for years, but in the past 3 years important organizations and
industry leaders have added new warnings with much stronger language
that not only change recognized best practices, but actually challenge the
fitness and safety of older placement methods altogether.
Introduction

Can we rid ourselves of the
problem by dumping the
system itself?
Sadly, we are learning
through SCADA and AMI
that there is actually more
backflow occurring at the
premise than we previously
suspected.
Introduction

And with this new risk realization comes a new interested party: The
insurance company. Because of this very public commentary from experts
and leading groups, casualty carriers, through subrogation, have new
weapons for damage recovery. And anytime the accused designer is able to
demonstrate that local government contributed, whether materially or
passively, to the poor design, the water district and/or building authority
may be at risk for the liability.
Introduction

• Water Districts NEED
Premise Isolation in
order to fulfill their EPA
mandate; and
Bottom Line:
“…. The return of any water to the
public water system after the water
has been used for any purpose on
the customer’s premises or within the
customer’s piping system is unacceptable
and opposed by AWWA.…”
• Premise-Isolation design details and specifications need to be provided to
civil engineers because of their general familiarity with standard details
and their comparable lack of familiarity with backflow systems.
AWWA’s preamble to the Cross Connection Control Manual,
published by EPA
Introduction

1. Water utilities are seeking more
premise-isolation.
2. That more containment systems are
being specified as RPZ regardless of
hazard threshold.
3. AWWA, ASPE, & the legal community
recognize “outside aboveground” as
‘best practice’ for premise isolation.
This presentation will show…
Introduction

1. Design differences DC vs. RPZ; Why it matters
2. Current placement practices and the problems with each
3. The real flood risks of indoor RPZs?
4. The real cost of indoor containment?
5. The explosive growth of the RPZ and how it impacts M/P Es
6. What are the “Best practice” examples around the U.S. for containment BPAs?
7. How do we encourage transitioning this task to the civil engineering discipline?
Today We’ll Cover…
Let the Civil Designer Deal with Containment System

2 types of backflow Preventers:
DesigndifferencesDCvs.RPZ
Double-Check Valve
Assemble, DC or DCDA
Reduced Pressure Zone
Valve Assembly, RP RPDA
A designer may specify one of two types of BFPs for premise isolation. Up until
recently, the decision for which assembly to specify was based solely on the
perceived hazard to the waste water system created by the processes of the end
user. High hazard (better named, high waste-hazard) uses were required to utilize an
RPZ. Uses that did not pose a risk to the waste water were allowed to use a DC.
1. Design Differences (and why it matters)

2 types of backflow Preventers:
Double-Check Valve
Assemble, DC or DCDA
Reduced Pressure Zone
Valve Assembly, RP RPDA
For example, a medical facility or a chemical plant triggered the requirement for an
RPZ while an office or simple retail user would be allowed to use a DC or, depending
on the municipality, no premise isolation system at all.
Now, as we will discuss below, many purveyors are requiring RPZs on all premise
isolation systems because of the inherent limits of protection provided by the double
check valve for the public water supply.

DC: Low hazard?
Public
(Supply)
side
Property
(Private)
side
Flow
The Double-check assembly was developed in the 1950s for the fire industry. And
for many years it was regarded as a satisfactory solution. The design is simple. Any
time system-water pressure on the property (private) side exceeds the system
pressure on the city (public) side, two redundant check valves close and water
stops flowing backwards.

DC: Low hazard?
But no remedy exists in the event of a malfunction of the valve closures or if
debris in the water line causes the valves to not close completely. Additionally,
The DC is a closed, or blind system making detection of any failure impossible
without a field test performed by a licensed tester. Today, millions of DCs are in
service that may have failed. When a Florida city began its annual testing program
in 2010, it found 52% of the valves in service had failed with no way to determine
how long they had been inoperable.
Public
(Supply)
side
Property
(Private)
side
Flow

RPZ: Fail-safe against returning water
Flow
Property
(Private)
side
Public
(Supply)
side
The RPZ emerged in the 1970s as a remedy to the double-check limitations. Like
the DC, it incorporates 2 redundant check valves. But unlike the DC, the RPZ
incorporates a hydraulically operated differential relief valve directly beneath the
# 1 check valve. It is this relief valve’s placement (along with the universal laws of
hydraulics) that make this a fail-safe solution for water purveyors. As elegant as
the design is, it comes at a cost. And that cost is the surrounding area.

Flow
Property
(Private)
side
Public
(Supply)
side
As the DC reveals, valves fail. But when they fail in an RPZ, the assembly is
designed to create a deluge event directly under the assembly so that no
contaminated water returns to the public water supply. Because of the danger of
contamination, no water from the relief valve may be piped directly from the
assembly. It must release into the atmosphere away from any piping. Watch this
short video revealing an actual discharge.

Flow Stop
In a flow-stop situation the water
between the check valves will often
drain out the relief valve. Some think
that that event defines the limit of
what water can ever flow into a drain.
Not so.

Loss of pressure
#2 valve
blocked
#2 valve
blocked
Consider a flow-stop situation, one that
might naturally occur at the end of the day.
If you look closely, you can see that a small
pebble has lodged in the #2 check valve.
Now let’s say there’s a fire around the
corner that causes back siphon at this point
in the system.
Because the # 2 check valve is not closing,
all the water that has been delivered to the
building will continue to flow out the relief
valve until the private lines are cleared. If
this is a four story building, that’s a lot of
water!

#1 valve
Failure
#1 valve
Failure
Normal
delivery
pressure
Now consider a failure of the #1 check
valve. Under normal operating conditions,
this failure would go unnoticed. After all,
water is being called for by the user
through the opening of taps. The water
flows in undeterred.
But with this imbalance in the system,
changes in demand tend to rock the
remaining valves open and closed
sporadically.
Demand

#1 valve
Failure
#1 valve
Failure
Blockage
relief
valve
Blockage
relief
valve
Demand
Normal
delivery
pressure
This creates the conditions for the “perfect
storm” scenario. The imbalance created by
the # 1 failure makes the relief valve more
prone to opening momentarily, allowing
debris to block the closure of that valve.
Under such conditions, a constant flow of
delivered water will begin to flow directly
out the relief valve. This reduces water
pressure for the user, but delivery will
continue.

No
demand
Normal
delivery
pressure
The real damage begins when the user
stops using water such as at the end of a
work day.
With the relief valve blocked open and the
# 1 valve inoperative, all the water that the
purveyor can provide will flow unabated
out the relief valve wherever it might be,
and continue until the water source is
interrupted.
This is the scenario that must be avoided:
the perfect storm.

This picture was tweeted last summer by a
Nashville backflow tester. He was called to
a multi-story office building on a Sunday to
inspect a “malfunctioning backflow
preventer”. By the time he completed his
service of the assembly, a small pebble was
all he recovered from the 8” RPZ in the
background.

This was the scene
when he arrived.
By the way, the RPZ
was working perfectly
before and after the
call, behaving precisely
as it was designed to.

 Above ground in an enclosure
 Inside a building
 Inside a vault
3 options for backflow preventer placement
2. Placement Practices

 Inside a vault
A subterranean vault would have to be considered the legacy method still
widely practiced among designers today but as most of you know, an RPZ
can never be installed below grade . Beyond the issue of being unsuitable
for RPZs however, there are compelling reasons to discontinue the use of
vaults altogether.

We’ve all seen the extraordinary measures
OSHA imposes to legally access vaults for
maintenance tasks. fresh air exchange hoses,
tents, extra men. The costs are more and more
prohibitive but frankly, the risk of serious injury
is real as well. But beyond the cost of safety for
onsite workers, liability issues persist.
 Inside a vault
1. Safety

When a vault floods like this one, the
mandatory test cocks are submerged, and in
that event, a violation of the International
Plumbing has already occurred. Consider what
would typically make up the constituents of
that water. Runoff of lawn chemicals alone
make this a clear and present danger to the
water supply.
 Inside a vault
2. Liability

In fact, it led the USC Foundation of Cross
Connection & Hydraulic Research in 2005 to
change their recommendation of even double
check BFP installation in vaults.
““The foundation’s recommendation would be to
install the double check valve above grade.”
- USC-FCCHR “Crosstalk, Summer 2005
 Inside a vault
2. Liability

The foundation added stronger language in
2014.
“When a backflow preventer is installed below
grade, the vault or pit in which an assembly is
installed may fill up with water, The water in the
pit could create a cross-connection between the
water in the pit and the backflow preventer
through the test cocks. This may occur whether
the test cocks are opened or closed….”
- USC-FCCHR “Crosstalk, Summer 2014 ..
2. Liability
 Inside a vault

Buildings, through their normal life of changing
tenants over time, change uses with respect to
hazard levels, and hazard levels, or more
precisely, the named high-hazard threshold,
has become a moving target.
 Inside a vault
3. Changing Demands

Around the corner from our Nashville office, I
snapped this picture. It sits in front of a
warehouse owned by an automotive dealer.
When they bought the property and erected
the building, they put a double-check BFP
down in that vault with the meter.
 Inside a vault
3. Changing Demands

A few years later, the city changed an
ordinance that redefined their particular use to
high-hazard. When they sought a permit to
upgrade the HVAC system, the city forced them
to change to an RPZ. So after constructing this
huge vault, they now leave it almost empty
with an RPZ in an enclosure perched on top of
it. They easily paid 3X the necessary cost
because they began with a “DC-only” solution.
Designers need to contemplate these latter-
day retrofits as they make design decisions.
 Inside a vault
3. Changing Demands

 Inside a vault
If the double check valve is commonly installed in a vault, then equally
common is that the RPZ is installed in an indoor location.

1. Space allocation/Accessibility
The space provided for an indoor BPA is
routinely inadequate as provided by the
architect. That’s because giving up space that
would otherwise add value is being allocated
as non-revenue space. Non-revenue space is
the enemy of every development project.

The BPA pictured cost tens of thousands in
property value. Even a mere 3” indoor BPA
will cost a developer $6,000 to $9,000 more
than an outdoor installation in a heated
enclosure.
1. Space allocation/Accessibility

2. Professional liability: indoor flooding
Here’s what the American Society of
Plumbing Engineers advise about indoor RPZs.
“Before an RPZ is located, consideration should be
given to both how much water will be discharged,
and where it will drain. Consideration must be given
to the drain system to assure the drainage system
can handle the load. If a drain is not capable of
accepting the flow, other choices as to the location
of the valve, such as outside in a heated enclosure,
should be made.”
-2006 ASPE Plumbing
Engineering Design Handbook, vol 2, p 70

As we have illustrated, an RPZ, behaving as
designed, creates a sudden flood.
We’ll cover these risks more deeply below.

In 1996, the American Society of
Sanitary Engineers (ASSE) developed a
quality and safety standard for
aboveground enclosures as a product
class. It’s known as ASSE-1060 and it
addresses 5 concerns.
•Freeze protection to −30°
•Vertical load strength of 100 PSF,
•Full flow drainage capacity, etc.
•Reliable Access
•Keyed Security
1. Quality, 2. Safety, 3. Security

Moreover, they took the guidance
further by identifying all possible
climate conditions and defining
appropriate guidance for Freeze-
prone areas (Class I); Frost-only areas
(Class II); and warm areas where no
climate control of any kind is required
(Class III).

This widely accepted standard
simplifies the specification process for
designers. By naming ASSE-1060 and
the appropriate class, there will be no
surprises upon delivery.

Indianapolis attorney, Doug Cregor has been the leading
attorney in the U.S. specializing in cross-connection
control litigation and advocacy. He is quoted in Plumbing
Standards Magazine as follows…
4. Legal endorsement
Douglas Cregor, Esq.

““An outdoor, aboveground BFP installation may be theAn outdoor, aboveground BFP installation may be the
best way tobest way to
1) reduce the owner1) reduce the owner’s exposure to damage caused by’s exposure to damage caused by
flooding and the corresponding water contaminationflooding and the corresponding water contamination
caused by a cross-connection; andcaused by a cross-connection; and
2) reduce the legal liability of the design engineers, the2) reduce the legal liability of the design engineers, the
installers, and the certified testers whose professionalinstallers, and the certified testers whose professional
actions, in part, may have otherwise caused the floodingactions, in part, may have otherwise caused the flooding
harm. The water industry has a nationally acceptedharm. The water industry has a nationally accepted
design criteria in ASSEdesign criteria in ASSE’s Standard-1060 to protect these’s Standard-1060 to protect these
installations. It’s a win-win-win ‘insurance policy’.installations. It’s a win-win-win ‘insurance policy’.
Douglas Cregor, Esq.
4. Legal endorsement

3. The Real Flood Risks of indoor RPZs
This flood occurred
in a hospital
mechanical room
causing over $1M
in damage.

You are looking at
2 sides of one wall.

On the left, we see
that the sudden
water flow and
volume moved the
wall into the next
room (right photo),
which happened to
be a telephone and
low-voltage wiring
room.

The insurer sought
recovery from all
the risk holders
including the
engineer, architect,
contractor,
subcontractor, and
even the most
recent recorded
tester;

While the details of
who paid what
were not made
public, we do know
that the property
insurer was made
whole by one or
more of the listed
defendants.

In times past, this
event would have
been seen as an
unforeseeable
casualty, a pipe
burst. But insurers
have been listening
to the next part of
the discussion. This
commentary from
experts changed
everything.

So if an RPZ is designed to dump water, then drain
capacity is the issue. The chart on the right is from
the manufacturer of the BPA seen in the previous
flood photos. It illustrates the anticipated flow rate
from the relief valve at various pipe sizes and at
various pressures. Note that the assembly shown will
flow 375 GPM at 85 PSI. A 4” drain pipe with a 1%
fall rate evacuates clean water at a maximum rate of
93 GPM. If that device is flowing at 375 GPM and
your clearing 93, then you are flooding at a rate of
282 GPM.

An article published June 2013 in
the Chicago chapter of the
American Society of Plumbing
Engineers written by David
DeBord, a former president of
that organization, and current
Education chair of the national
ASPE, states all these facts better
than I can.
3 .The Real Flood Risks of indoor RPZs

He uses the Manufacturer’s data
supplied by a different
manufacturer, and he uses a 65
PSI instead of my 85, but he
actually does the math in the
article and offers FLOOD rates or
219 GPM for 2 1/2 and 3”; and
flood rate of 482 GPM for 4” and
above.

He concludes that regarding
indoor RPZs…

Backflow Failure
Watch this video showing a
check valve failure and the
resulting flood water flow.

2. Indoor RPZs Reduce the rentable
square footage of a building reducing
revenue & property value
The space provided for an indoor BPA is routinely
inadequate as provided by the architect. That’s
because giving up space that would otherwise add
value is being allocated as non-revenue space. Non-
revenue space is the enemy of every development
project.
4. The Real Cost of Indoor BPAs

Charlotte: 32.000 SF
Columbus: 36.000 SF
Suffolk Cty: 33.333 SF
Arlington: 32.000 SF
Average: 33.325 SF
Consider the average square footage required
for just a 3-inch indoor in-line backflow
preventer. To the right, four representative
cities are represented. The average required
space is 33.325 SF.
Assuming a discount rate of 9%, rent value of
$30 per foot annually, and a 25 year life, the
net present value of that space to the property
owner is $12, 156.48.
Arlington, TX: 32 SF

Average: 33.325 SF
Annual Rent Value
(based on Class A Office
@ $30/sf)
$999.75
25-year Cash Flows
(based on 2.5% inflation)
$34,149.22
Net Present Value
(based on 9% discount
rate)
$12,156.48
Assuming a discount rate of 9%, rent value of
$30 per foot annually, and a 25 year life, the
net present value of that space to the property
owner is $12, 156.48.

NPV:
Landlord has lost this amount of value
by placing CBPA inside.
$12,156.48
CONSIDER:
1.If space is recaptured for rental value, what will my alternative cost be?
2.Will placing the system outside cost more or less than $12,156.48?
3.If it’s less, then how much less? (I don’t like the look of a box outside.)

Aboveground heated enclosure
for 3” BPA with heat.
Option A:
Use conventional model
e.i., Watts 957 NRS
Safe-T-Cover 300-AL-H
$3,266.00
72 X 38 X 22 = 60K CI
Option B:
Use new ”n-type” model
e.i., Watts 957N NRS
Safe-T-Cover 200SN-AL-H
$1,120.00
46 X 38 X 19 = 33K CI

$1,000
$1,120
$1,800
$3,920
$3,266
$1,200
$1,800
$6,266

Indoor
CBPA
$3,920.00
plus assembly
$6,266.00
plus assembly
$12,156.48
plus assembly
Owner’s Cost: 3” Domestic line

“How much more value does my building have with the additional
rent?”
ANSWER:
Year Annual Rent*
1 $999.75
PropertyValue*
$10,289.09
5 $1,103.54 $11,357.23
10 $1,248.55 $12,849.67
15 $1,412.62 $14,538.22
20 $1,598.25 $16,448.66
25 $1,808.27 $18,610.15
* - Today’s dollars: Assumptions: Annual rent growth of 2.5%; 5% vacancy; 35% operating expenses;
capitalization rate of 6%.
Owner’s Property Value

No more DCs on
commercial or industrial
properties.
Chicagoland, IL
TheexplosivegrowthoftheRPZ
Elgin, October 2012
5. The Explosive Growth of the RPZ

Chicagoland, IL
Naperville, April 2013
Naperville already required RPZs on their commercial irrigation systems, but after
Elgin’s action, they too outlawed DCs, and in fact, extended mandatory RPZ use on
fire line systems as well.

Atlanta Area, GA
Roswell, August, 2014
Roswell detailed two methods of RPZ
placement, one indoors for small sizes,
and one outdoors for larger sizes.

Atlanta Area, GA
The drawings for the indoor method
explicitly address drain system
requirements and force designers to
reconcile the flood rate risks with
specific drainage system capacities

Atlanta Area, GA
The chart shows that unless the
designer is willing to install an 8”
drain system all the way to the
sewer inlet, he cannot utilize an
indoor solution for any pipe size
larger than 2 inches.

Atlanta Area, GA
And the outdoor method mandates an
enclosure that is ASSE-1060 compliant.

Delaware, June 2013
Columbus Area, OH

North central Texas
Alpine
Bedford
Boerne
Carrollton
Cleburne
College Station
Denison
Farmington
Farris
Franklin
Grand Prairie
Haltom
Texarkana
Waco
Waskom
White Settlement
Addison
Arlington
Buda
Cedar Hill
Colleyville
Crowley
Denton
Duncanville
Fort Worth
Franklin
Gainesville
Highland Village
Midlothian
Roanoke
Round Rock
Saginaw
Same language added to muni code

Alpine
Bedford
Boerne
Carrollton
Cleburne
College Station
Denison
Farmington
Farris
Franklin
Grand Prairie
Haltom
Texarkana
Waco
Waskom
White Settlement
Addison
Arlington
Buda
Cedar Hill
Colleyville
Crowley
Denton
Duncanville
Franklin
Gainesville
Highland Village
Midlothian
Roanoke
Round Rock
Saginaw
DFW, TX
Fort Worth, July, 2010
Since then, all these
Texas cities have
added it to their own
code.

Central VA
Lynchburg, 2008
Lynchburg has
required RPZs on all
non residential
connections for almost
a decade. This includes
domestic, irrigation,
and fire lines.

Mountain West
Denver, February, 2013
In 2013 Denver Water
added new standard
details for 3” and larger
RPZs to be installed
outdoors.

Mountain West
Denver, February, 2013
They even call for double
checks for public park
drinking fountains to be
installed above ground in
a heated enclosure.

Seattle, WA
Raleigh, NC
Charlotte, VA
Austin, TX
Nashville, TN
Albuquerque, NM
Long Island, NY
Denver, CO
Las Vegas, NV
Lynchburg, VA
Columbus, OH
Chicago. IL
Forth Worth, TX Roswell, GA
Longview, WA
Arlington, TX
Gwinnett Cty, GA
Chesapeake, VA
Olympia, WA
Kent, WA
Franklin, TN
All these cities have made changes
whereby RPZ use has been
expanded either by lowering or
eliminating the hazard threshold
for use on domestic water lines in
the past 5 years. (These are the
cities we know of….)

Charlotte, NC
Denver, CO
Columbus, OH
Roswell, GA
Arlington, TX
Gwinnett Cty, GA
Las Vegas, NV
6. What are the Best Practice Examples
around the Country
BestPracticeExamples

Perfect StormConsider the ‘worst case scenario’ of a
water volume discharge of a
containment backflow prevention,
namely, an uncontrolled discharge
caused by a failure of the #1 check
valve contemporaneous with the relief
valve being stuck or propped open by
debris. If there is no faucet demand
within the commercial premise, such
as over night, then this perfect storm
produces an unmitigated flow of all
available water through the relief valve
continuously. The management of this
sudden water deluge is a significant
hazard. As severe as the most severe
storm water runoff event.
Special Insert
This hazard is clearly work found within
the civil engineering discipline rather than
the plumbing engineering discipline.
Designing and specifying any outdoor
containment BPA – even if it is placed
within the jurisdictional boundaries of the
plumbing engineer, is asking for trouble.

A survey of 1869 civil and mechanical
engineers was conducted by Safe-T-
Cover and EnviroDesign Management
over a 22-month period ending in
Spring, 2016. The survey followed a
professional learning module
delivered by EnviroDesign and was
managed and tabulated by Benchmark
Email Services. Excluding delivery
failures, 1220 were delivered and
opened. The following 2 slides show
the questions in the short survey and
the responses.
7. How do we Encourage transition to Civil
Engineers

Engineers

 Develop a firm-level policy
 ASPE local chapter dialog with local water purveyor
 Encourage best practices learning
 Publish standard details and drawings consistent with
best practices
Engineers

 Plumbing engineers are facing new liability risks from insurance
carriers, revealed by new warnings and commentary from industry
leadership regarding indoor containment RPZs.
 The need to address sudden flood water flows disqualifies MEP
from CBPA Design.
Take-Aways
 Your local water district must be encouraged to adopt new details
and guidelines that promote best practices and adoption by CEs.
 Indoor placement of 3” & > RPZs adds irrational risk for PO &
designer.
 Placing the CBPA inside costs PO $000s more than outside.
 Because of the need for pure water in the public water supply and
the undetectable nature of the DCs, purveyors are demanding
more RPZs and ignoring the legacy hazard guidance.
 In order to plan for hazard-change and rule-change retrofits, even
DCs should be positioned in a location suitable for RPZ.
 RPZs are designed to engulf the immediate surrounding area.

Please complete the session evaluation in the
ASPE 2016 app or online at aspe.org/sessions.
Your feedback is greatly appreciated.
CEU certificates will be emailed to attendees
within 2 weeks after the conference.
Thank you

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