This presentation focuses on the increasingly popular move by public water systems to require RPZ backflow preventers on all water lines.
This is the third of a three part series on backflow preventer installation, standard details, and best practices. The series focuses on three key facts: Water utilities are seeking more premise-isolation cross connection control. More containment systems are being specified as RPZ regardless of hazard threshold. The AWWA, ASPE, & the legal community recognize “outside aboveground” as ‘best practice’ for backflow installation.
Part 1: http://www.slideshare.net/CraigCarmon/backflow-best-practices-and-standard-details-part-1
Part 2: http://www.slideshare.net/CraigCarmon/backflow-best-practices-and-standard-details-part-2
2. Part 3: The Explosive Growth of RPZs
Premise Isolation Backflow Prevention:
Best Practices & Standard Details
3. Premise Isolation: Best Practices & Standard Details
….Definitions and term use:
Isolation backflow prevention: In addition to the lavatory and water fountain, most buildings’
plumbing systems include fixtures that are designed to clean contaminated equipment,
carbonate beverages, and even infuse chemicals and detergents. Many of these processes
create dangerous and toxic substances. If these substances were allowed to reverse back into
the building’s fresh water piping, an event known as backflow, it would create serious health
hazards for the individuals on site. Building authorities deal with these risks by specifying
appropriate backflow preventer assemblies at those specific locations where contamination is a
risk. The term for this solution is “isolation backflow prevention” because a special plumbing
apparatus known as a backflow preventer isolates high-hazard fixtures and equipment at the
point of use from the rest of the on-site piping system.
4. ….Definitions and term use:
Containment or ‘Premise Isolation’ backflow prevention: For public water systems, water that
has been delivered through its water meter to a water customer is only done safely and
responsibly when there is no possibility that that water will return back from the customer to
the water system, an event (also) known as backflow. Disparate groups within plumbing,
design, and water management have devised their own favorite terms for this system. The
plumbing community prefers “Containment backflow prevention” because such systems
contain delivered water at the subscriber’s premises; On the other hand, water districts tend to
prefer “Premise Isolation”. It is important to understand that whether called Containment or
Premise Isolation, we are referring to the task of eliminating backflow at the Point of Supply
from the public water system.
This presentation is limited to the recognized best practices of these containment or premise
isolation systems.
Premise Isolation: Best Practices & Standard Details
5. Introduction
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.
Premise Isolation: Best Practices & Standard Details
6. 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.
Premise Isolation: Best Practices & Standard Details
7. 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.
Premise Isolation: Best Practices & Standard Details
8. Assuming the legal rights of a person for whom expenses or a debt has been paid.
Typically, an insurance company which pays its insured client for injuries and losses then
sues the party which the injured person contends caused the damages to him/her.
Introduction
Because of subrogation, the water district needs to
demonstrate that no unsafe methods are
promoted by their plans review teams. The best
way to demonstrate that is with published
standard details and drawings that are consistent
with recognized best practices.
Premise Isolation: Best Practices & Standard Details
9. Introduction
…Meanwhile, at the 2016-17 bi-annual conference of the American Society
of Plumbing Engineers, one popular learning module titled “Let the Civil
Engineer Deal with the Containment Backflow System” suggests that
leadership is seeking reassignment of the premise isolation backflow system
design to the civil discipline. No surprise, other than how long it took to
realize… Plumbing engineers have nothing to gain and everything to lose
when they specify indoor RPZs because
• The flood risks now being realized from indoor installations of RPZs is
extraordinary;
• Designing for outdoor placement includes grading and surface contouring
for sudden flood water flows; a task that is beyond the scope of a
plumbing engineer’s training or expertise.
Premise Isolation: Best Practices & Standard Details
10. Introduction
According to a survey of 1220 U.S. civil
and plumbing engineers conducted
over a 19‐month period, 3 out of 4 say
they need local water authorities to
provide standard details for outdoor
aboveground backflow preventer
systems.
You can read more about the results of
this survey here.
Premise Isolation: Best Practices & Standard Details
11. • Water Districts NEED
Premise Isolation in
order to fulfill their EPA
mandate; and
Introduction
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
Premise Isolation: Best Practices & Standard Details
12. 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
Premise Isolation: Best Practices & Standard Details
13. The Explosive Growth of the RPZ
Water purveyors are increasingly requiring RPZ backflow preventers on all
new lines.
Additionally, either of two future events will require a DC assembly to be
upgraded to an RPZ - an outcome that is becoming quite common, and will
cost the owner thousands of dollars in retrofit expense plus the continued
lost opportunity cost from an over sized mechanical room. This happens
either when the tenancy changes from low hazard to high hazard through the
normal leasing and re-leasing process; or the purveyor changes its definition
of what constitutes "high hazard" and now your low hazard user will be re-
classified as a high hazard user.
Here are some examples of the cities leading the way with this trend.
Premise Isolation: Best Practices & Standard Details
14. No more DCs on
commercial or industrial
properties.
Chicagoland, ILTheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Elgin, October 2012
Premise Isolation: Best Practices & Standard Details
15. Chicagoland, ILTheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
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.
Premise Isolation: Best Practices & Standard Details
16. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Atlanta Area, GA
Roswell, August, 2014
Roswell detailed two methods of RPZ
placement, one indoors for small sizes,
and one outdoors for larger sizes.
Premise Isolation: Best Practices & Standard Details
17. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Atlanta Area, GA
Roswell, August, 2014
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
Premise Isolation: Best Practices & Standard Details
18. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Atlanta Area, GA
Roswell, August, 2014
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.
Premise Isolation: Best Practices & Standard Details
19. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Atlanta Area, GA
Roswell, August, 2014
And the outdoor method mandates an
enclosure that is ASSE-1060 compliant.
Premise Isolation: Best Practices & Standard Details
20. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Atlanta Area, GA
Gwinnett County, December, 2016
Gwinnett County is the latest to add
standard details for aboveground
installation. Note they have chosen to
lay out the meter vault as well in order
to contextualize the entire layout.
Premise Isolation: Best Practices & Standard Details
22. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
DFW, TX
Fort Worth, 2010
In 2010, Fort Worth
added this language
to their code, often
referred to as the
“undetermined
tenant clause”.
Premise Isolation: Best Practices & Standard Details
24. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Central VA
Lynchburg, 2008
Lynchburg has required
RPZs on all non
residential connections
for almost a decade.
This includes domestic,
irrigation, and fire
lines.
Premise Isolation: Best Practices & Standard Details
25. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Mountain West
Denver, February, 2013
In 2013 Denver Water
added new standard
details for 3” and larger
RPZs to be installed
outdoors.
Premise Isolation: Best Practices & Standard Details
26. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
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.
Premise Isolation: Best Practices & Standard Details
27. TheexplosivegrowthoftheRPZ
The Explosive Growth of the RPZ
Another reason: new form factor
12’
6’8”5’2”
5’4”
Another key reason for growth of outdoor installations is the new form factor of
the n-type assemblies which reduce the visual envelope of the enclosure by as
much as 70% without increasing the net cost.
Premise Isolation: Best Practices & Standard Details
28. Designer Survey Results
Premise Isolation: Best Practices & Standard Details
A survey of 1869 civil and
mechanical engineers focused on
standard details 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. 1220 were delivered
and opened. The following 2 slides
show the questions in the short
survey and the responses.
31. The public water supply is unprotected from returning water without a
premise isolation system. RPZs are only fail-safe solution.
The duties of the building/plumbing authority and the plumbing code do not
wholly satisfy the duties of the water utility.
Indoor RPZs 3” and larger are perpetual floods risks.
The need to address sudden on-site water flows disqualify MEPs from outdoor
premise isolation design, even if within MEP halo.
Civil engineers are unfamiliar with BPA installations and need standard
details from water authorities.
Take-Aways
A broadly adopted region-wide set of guidelines would save cities 000s of
hours in plans-review time.
Premise Isolation: Best Practices & Standard Details
32. Safe-T-Cover's blog: Updated weekly with articles on backflow prevention,
standard details, and best practices.
Enclosure Design eBook: Learn the 5 design considerations for
aboveground enclosures
Recent story on decision to add standard details by the city of Arlington, Texas
Trends in Backflow Preventer Installation: A downloadable guide to the latest
trends in backflow best practices.
Additional Resources
Premise Isolation: Best Practices & Standard Details
The Eng commty: struggling w/ new professional liability risk involving the location of PremISO Backflow preventer systems.
not because new design practice,
but because of new information about the old practices.
Slow trickle of warnings for years,
* past two years: imp orgs and ind’ry leaders have added new warnings, much stronger lang:
not only change recognized best practices,
but actually challenge the fitness and safety of older placement methods altogether.
Can we rid ourselves of the problem by dumping the system itself?
More backflow is occurring than was previously believed
And with this new risk realization comes a new Interested Party. The insurance company.
Because of this very public commentary from experts, they now have new weapons for damage recovery.
And anytime the designer is able to demonstrate that local government was causal to the poor design,
they, through the magic of subrogation,
have at least one more pocket to pick.
* The Local Water Authority.
MEANWHILE, In the October Bi annual conf of the ASPE,
Plumbing engineers are seeking reassignment of the Prem-Iso BP system design to the civil discipline due to
1. the flood risks now being realized from indoor installations of RPZs;
2 .the realization that designing BPAs for outdoor placement includes grading and surface contouring for
sudden flood water flows which are beyond the scope of a plumbing engineer’s expertise.
According to a survey of 1220 civil and plumbing engineers in North central Texas
conducted over a 19‐month period, 3 out of 4 say they need local water authorities to provide standard details for outdoor aboveground backflow preventer systems.
The bottom line: Water districts need premise isolation, and
Premise isolation design specifications need to be provided for civil engineers.
Consider these facts.
So let’s look at the considerations.
Safety, Liability, and changing demands
* 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.
* When a vault floods like this one, the mandatory test cocks are submerged, and in that event, a violation of the International Plumbing has likely already occurred. The water may look clean, but 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. 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.
* (READ)
Finally, Changing demands. Engineers are obviously preoccupied with new construction.
But 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.
Around the corner from our office in Nashville, 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.
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. After constructing this huge vault, they now leave it almost empty with an RPZ in an enclosure perched on top of it. They paid three times for a single solution.
Now this enclosure – This is what happens all too often when tenants or hazard thresholds change in areas where no guidelines or Standard Details exist.
So what’s happening around the country that might help us understand where all this is going?
* We’ve been watching Northern Illinois. More specifically, the 7 most populous cities around Chicago.
* It all started in the fall of 2012 with Elgin. On October 24, 2012, they amended their domestic water service requirements as follows: (READ)
*A few weeks later, the city of Chicago amended their fire line guidelines as follows: READ
* Not to be left behind, in January of 2013 Naperville saw Elgin and raised them one, amending their guidelines to require RPZs on all commercial and and multi-residential new construction for each service, Fire, irrigation, and domestic.
So what’s happening around the country that might help us understand where all this is going?
* We’ve been watching Northern Illinois. More specifically, the 7 most populous cities around Chicago.
* It all started in the fall of 2012 with Elgin. On October 24, 2012, they amended their domestic water service requirements as follows: (READ)
*A few weeks later, the city of Chicago amended their fire line guidelines as follows: READ
* Not to be left behind, in January of 2013 Naperville saw Elgin and raised them one, amending their guidelines to require RPZs on all commercial and and multi-residential new construction for each service, Fire, irrigation, and domestic.
Within the Central Ohio area,
Columbus has articulated a rational middle-ground position for getting Backflow preventers out of harm’s way.
Recognizing that drain capacities for small sized RPZs CAN be accommodated with a typical 4” drain system, they detailed two methods of RPZ placement, one indoors for small RPZs, and one outdoors for larger sizes.
* 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
* And the outdoor method mandates an enclosure that is ASSE-1060 compliant.
Within the Central Ohio area,
Columbus has articulated a rational middle-ground position for getting Backflow preventers out of harm’s way.
Recognizing that drain capacities for small sized RPZs CAN be accommodated with a typical 4” drain system, they detailed two methods of RPZ placement, one indoors for small RPZs, and one outdoors for larger sizes.
* 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
* And the outdoor method mandates an enclosure that is ASSE-1060 compliant.
Within the Central Ohio area,
Columbus has articulated a rational middle-ground position for getting Backflow preventers out of harm’s way.
Recognizing that drain capacities for small sized RPZs CAN be accommodated with a typical 4” drain system, they detailed two methods of RPZ placement, one indoors for small RPZs, and one outdoors for larger sizes.
* 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
* And the outdoor method mandates an enclosure that is ASSE-1060 compliant.
Within the Central Ohio area,
Columbus has articulated a rational middle-ground position for getting Backflow preventers out of harm’s way.
Recognizing that drain capacities for small sized RPZs CAN be accommodated with a typical 4” drain system, they detailed two methods of RPZ placement, one indoors for small RPZs, and one outdoors for larger sizes.
* 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
* And the outdoor method mandates an enclosure that is ASSE-1060 compliant.
Within the Central Ohio area,
Columbus has articulated a rational middle-ground position for getting Backflow preventers out of harm’s way.
Recognizing that drain capacities for small sized RPZs CAN be accommodated with a typical 4” drain system, they detailed two methods of RPZ placement, one indoors for small RPZs, and one outdoors for larger sizes.
* 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
* And the outdoor method mandates an enclosure that is ASSE-1060 compliant.
Delaware, Ohio. In the 2013 release of their Infrastructure design guide, they now mandate RPZs in outdoor enclosures on all commercial, industrial, and institutional water lines.
Fort Worth, TX. Just a few months ago, Fort Worth updated their Design Standards Manual. Within it, they’ve defined what we’re calling the Tenant Provision.
[READ]
Fort Worth, TX. Just a few months ago, Fort Worth updated their Design Standards Manual. Within it, they’ve defined what we’re calling the Tenant Provision.
[READ]
In Central Virginia, the city of Lynchburg was one of the earliest adopters of the current trend toward RPZs. In 2008, they amended their construction guidelines as follows: [READ]
In the Mountain West, Denver, Colorado has long had the reputation of being a leader in infrastructure quality: In 2012 and 2013, Denver Water, one of the nation’s largest water purveyors, added specifications and drawings for above ground backflow preventer enclosures to their standard details. They make specific recommendations about 3” and larger RPZs and even small double check backflow preventers being deployed to aboveground enclosures.
Let’s look briefly at the new solutions emerging to deal the the need for less visual impact on property fronts that owners so desperately desire.
* This is the industry standard Watts 709 DCDA. It is housed by our Model 1000-AL. It’s 12 feet long and stands 6’8” tall.
* This is the Wilkins 450DA. It is housed in our Model 1000TLU880M.
* It’s 5’4” square and stands just 5’2” tall.
Not only does this solution accomplish the same plumbing solution and make a much smaller visual footprint,
* it also saves roughly 25% of the cost.
1.
2. Strong nat’l migration toward RPZ, away from DC with many standard details that have ceased to iteratively improve. That’s a business school way of saying Best practices are now evident because as time continues, cities are defining the same methods.
3. Indoor RPZ 2 ½” and larger cause floods and feed insurers. It’s not enough to say that some large indoor systems are poorly designed. If your building has a flange-sized RPZ inside and does not have at least an 8” drain system all the way to the sewer, then it fails the flood liability test and should not be there.
4. MEP engineers cannot stamp anything that is to be installed beyond 6’ of the building envelope so how can they design flange-sized RPZ systems at all?
5. Civil Engineers are not plumbers and need standard details provided by water authorities in order to properly design these systems.
6. Water authorities are driving these devices inside because “that’s the way everyone knows how to do it.” Continuing to direct and favor methods that are unsafe, or even less safe, expose the jurisdiction to liability risk.