OSFM PPT Template 1 - NCDOI€¦ · The drafting symbol for connection point ... 1996 NC Mechanical Code, although manufacturers may have required a 4” vent as part of the instructions

Code College

Section 102.2, 102.3, 102.4 –

Existing Work and New Work

interfaces

Dan Dittman, PE

Mechanical Code Consultant

1

102.2, 102.3, 102.4 New and Existing Work

The drafting symbol for connection point

between new and existing work

(almost-limited to PowerPoint symbols)

2


The purpose of this class is to point out

and discuss situations that are routinely

encountered, and how the code’s

flexibility can also lead to uncertainty and

the perception of inconsistency.

3


NC Mechanical Code Excerpt – Existing work

and additions

Here are the major code sections this paper is

going to concentrate on:

102.2 Existing installations. Except as otherwise

provided for in this chapter, a provision in this code

shall not require the removal, alteration or abandonment

of, nor prevent the continued utilization and

maintenance of, a mechanical system lawfully in

existence at the time of the adoption of this code.

4


And…

102.3 Maintenance. Mechanical systems, both existing and new,

and parts thereof shall be maintained in proper operating condition

in accordance with the original design and in a safe and sanitary

condition. Devices or safeguards which are required by this code

shall be maintained in compliance with the code edition under which

they were installed. The owner or the owner’s designated agent shall

be responsible for maintenance of mechanical systems. To determine

compliance with this provision, the code official shall have the

authority to require a mechanical system to be reinspected.

5


And… 102.4 Additions, alterations or repairs. Additions, alterations,

renovations or repairs to a mechanical system shall conform to

that required for a new mechanical system without requiring the

existing mechanical system to comply with all of the

requirements of this code. Additions, alterations or repairs shall

not cause an existing mechanical system to become unsafe,

hazardous or overloaded.

Minor additions, alterations, renovations and repairs to existing

mechanical systems shall meet the provisions for new

construction, unless such work is done in the same manner and

arrangement as was in the existing system, is not hazardous and is

approved.6


So… New work has to meet new code…

Well, maybe not, as long as you approve it…

7


In addition to the above sections, two related

sections are:

105.5 Approved materials and equipment.

Materials, equipment and devices approved by the

code official shall be constructed and installed in

accordance with such approval.

105.5.1 Material and equipment reuse.

Materials, equipment and devices shall not be

reused unless such elements have been

reconditioned, tested, placed in good and

proper working condition and approved.

AND… 8


In addition …

304.1 General. Equipment and appliances shall be

installed as required by the terms of their approval, in

accordance with the conditions of the listing, the

manufacturer’s installation instructions and this code.

Manufacturer’s installation instructions shall be

available on the job site at the time of inspection.

9


Contributing Factors

In the mechanical, fuel gas and plumbing trades,

the nature of the trade is to perform a substantial

quantity of change-outs and replacements of

equipment over the life of a structure.

Various analogies will be used through this paper

to illustrate the issue, hopefully to clarify the

situations by allowing more people to relate to the

replacement.

10


Contributing Factors of disagreement/perception of

inconsistent enforcement

When it comes to new work, the issue of “where

do I stop applying the present code?” is not an

issue.

11


When there is replacement work, “Where do I

stop applying the present code?” is almost

always a question, because you are many times

replacing only part of a system, and several

different elements could affect the decision.

Although the fact that the code may have changed

is commonly cited (blamed), there are other issues

that are equally a cause of something not being a

simple drop-in replacement. Several of the most

commonly encountered issues are:

12


13

The code as a scope of work

• Whether it was intended to or not, the code

many times becomes the de facto scope of work.

• If the installing contractor can get their target

payment (full profit margin) for true code-

required work, is there generally an issue?

• What happens if a citation for a code deficiency

happens after the job is bid or quoted?

• Now we have an issue.


14

The code as a scope of work

• Is there anything in the code, that says an installing contractor

has to do cited code deficiencies for free?

• No.

• However, is it a comfortable process to go back to the bldg.

owner and get more money?

• No.

• Is it sometimes easier to see if the code requirement can be

re-interpreted to make the citation go away?

• Show of hands?


Several of the most commonly encountered issues

are:

– Who is reading the code?

– Where does the “system” end?

– Product obsolescence

– Manufacturer’s requirements creating conflicts

– Change in consumer tastes

– Changes in the underlying standard that an

appliance is listed to

15


Let’s review some of these underlying causes

individually:

– Who is reading the code?

• The code is supposed to be equally applied by

whoever reads it.

• For this example, lets assume there are three

interested parties:

• building owner,

• installing contractor

• code official.

16


Interested parties

17

Code

BldgOwner

Code Official

Contractor


Let’s take these one at a time: Bldg Owner

Building owner reads:

105.5.1 Material and equipment reuse.

Materials, equipment and devices shall not be

reused unless such elements have been

reconditioned, tested, placed in good and

proper working condition and approved.

So, in the absence of a scope of work stating

otherwise, what are minimum expectations for all

the pieces connected to an air handler?18


Let’s take these one at a time:

Pieces

– Vent method

– Condensate drain method

– Auxiliary drain method (maybe)

– Electrical conductors

– Fuel supply (oil, gas, propane)

– General supports such as hangers, pad, etc.

19



Building Owner

– Is their reading of the code going to equal the

installing contractor and code officials reading?

– What if there is an issue down the road?

– Suppose concealed vent was cracked--moisture in

walls, drain line stopped up--water overflows into

space, pad allows grass to grow up into new unit if it

is substantially larger than original unit.

– These are some of the issues that arise.

20



Installing Contractor


installing building owner and code officials reading?


– Vent was cracked, moisture in walls, drain line

stopped up, water overflows into space, pad allows

grass to grow up into new unit if it is substantially

larger than original unit.

– Who is responsible for a failed system if an existing

part of the system later turned out to be deficient?

21



Code Official


installing building owner and installing contractor

reading?


– Access to unit, space really tight.

– Insufficient clearance for new unit.

– Is the jurisdiction going to be around a long time,

perhaps longer than the installing contractor?

i22


The code applies to the property generically and

without bias. In other words, it should read the same

and be interpreted the same whether you are the

Bldg Owner, Installing Contractor, or Code official.

In the absence of a supplemental scope of work,

the expectations of minimum code can vary from

the three parties most affected.

This presentation will attempt to identify and clarify

some of these situations.

i23


How many people in this classroom have had a

quote from a contractor given to them, and there

were numerous items labeled as : ”code required”

Furthermore, how many have had you go line-item-

by line item and see which ones truly were and which

ones were not?

If a code official requires something above minimum

code, what could happen?

i24


Product Obsolescence

The issue of product obsolescence is the most

familiar with people dealing with computers and

associated hardware, such as printers.

We all have had a printer that we absolutely loved,

for me it was the HP 720. That printer was

bulletproof, reasonably priced ink, and not prone to

jamming. It also came with the old LPT1

connector.

25



Well, if and when your computer dies, there is no

guarantee that the new computer will support the

older printers, either due to software or hardware

obsolescence.

If the computer industry went away from supporting

the LPT1 connected-printer, can you force the

computer company(ies) to install the required

connectors or software to make it backwards-

compatible for all time?

26



Chances are “no”. We may not like this, but there

is little an individual or even entire industries can

do about it (BetaMax?).

The industry and its trade groups will follow

whatever regulations they have put in place, but

those guidelines/regulations move and change with

advances in technology.

27



In the building world, a very common issue is an

hvac unit that has different refrigerants than the

original unit. As R-22 is being phased out, there

has been an initial spike in the cost of R-22, and

therefore repair of heat pumps and AC units with

R-22.

There are dry-ship replacement condensers that

allow the homeowner to retain the use of one part

of the spilt system but even that repair will likely

use some R-22.

28



It is unclear how long any manufacturer will

continue to make these dry-ship units for R-22

systems. As time goes on, the costs will start to

go down again for R-22, because there will be less

and less demand for it as more and more units are

completely R-410A or some other refrigerant such

as Ammonia.

29


Manufacturer’s Requirement Preventing

Backwards Compatibility

An example of this is old dryers sometimes were

installed with 3” vents.

There was nothing that prohibited this for sure until the

1996 NC Mechanical Code, although manufacturers

may have required a 4” vent as part of the instructions.

There are many, many vents that simply went from the

laundry room and out the wall, and there were no issues

and a 4” vent was likely used. 31




However, in cases where the exhaust duct had to go in

the cavity of a wall constructed of nominal 2x4 studs,

the 4” duct would not fit, and 3” was used on an

unknown number of occasions.

Although exhaust duct work of course isn’t quite like

sanitary waste because there are not large solids (there

are very small solids, lint) there are definitely

requirements that prevent the use of 3” exhaust duct

now. 32




However, what do you do if the new dryer specifically

states, or warns against using anything other than 4”

exhaust duct, but the existing exhaust ductwork is 3”,

and more than likely installed in the cavity of a wall?

Is this a safe installation?

Is it an apartment complex?

Is it an immediate life-safety concern?

Will it void the warranty? Etc. etc.33


Change in consumer Tastes

Many newer appliances simply do not fit in

the same spaces that the original appliance

was installed in. Washing machines and

dryers are many times much larger than the

original space was provided.

What if the new appliance does not have

adequate clearance to combustibles?

34


Change in consumer Tastes

What if the makeup air openings are

obstructed by the new wider/taller

appliance?

Is this a safe installation?

Is it an immediate life-safety concern?

Will it void the warranty? Etc. Etc.

Does it matter who calls in? The Bldg

Owner, the Contractor, the Code official?35


Changes in the underlying standard that an


When a product is listed, it generally has to pass

a set of tests to demonstrate its performance and

safety under various conditions.

Sometimes, the test standard itself changes for

various reasons.

36




Then, field conditions may make it difficult to

replace a product or piece of equipment in the

field that now would no longer meet the

upgraded requirements in the standard.

The one issue that comes to mind is the standard

for field-applied grease duct wrap.

37




At one time, it used to be allowed to have only a

single layer, but then the testing may have

determined one layer was inadequate, and the

requirement is now for two layers.

38




Many times there is an architectural chase built

around a grease duct; if the grease duct were in

need of replacement due to it warping during a

grease duct fire, could I go back with a single

layer of wrap due to space constraints?

39




This is actually easy to answer, and the answer is

“no”.

Typically the grease duct size is not critical, and

it could be downsized a little to make up for the

increase insulation, but I hope this illustrates the

issue of underlying standards changing.

40


Code –Related Contributing Factors

In addition to things beyond the control of the code-

making and code enforcement process, there are directly

related to code, and they can sometimes have an effect on

how a replacement can be done. Code enforcement deals

with this on a frequent basis.

41


Code –Related Contributing Factors

There are two basic paths to investigate here:

– An issue that was not directly prohibited in prior code

cycles, but is now directly prohibited.

– Code simply was not met

42


An issue that was not directly prohibited in prior code cycles, but is

now directly prohibited.

There are several occurrences of this in the code. An issue that is

recurrent is the use of UL 181 listed flexible duct being used to

penetrate a wall or ceiling/floor separating a garage from the

living space.

43




Is any UL 181 flexible ductwork penetrating the required

separation “lawfully in existence.”

In the 2002 NC Residential Code, it is the first time there is a

prescriptive means of penetrating the required separation with

anything, and it requires the 26 ga. Metal ductwork.

44




So what happens to all the houses where flex duct is installed

penetrating the floor or wall that is between the garage and the

dwelling space?

The installation instructions from UL 181 flexible ductwork

available today indicate it cannot be used to penetrate any rated

assembly. It would be difficult to locate installation instructions

from pre-1993, and the UL 181 test from then may not have

addressed it directly.

45




Based on the lack of directions allowing it, and the clear

prohibition against it now, it has been my interpretation that it is

not “lawfully in existence”, but how to remedy it is left to the

individual jurisdictions.

We will revisit this later in the presentation.

46


Code simply was not met

Why am I responsible for something you missed?

Prior to 1979, there was not mandatory code enforcement. There

was a code, but the responsibility for meeting it was the building

owner, installing contractor, and, if applicable, design

professional. We routinely have instances from the field where

the age of the construction or retrofit is known, and it is clear the

code was not met for the time frame under which it was installed.

47



There are three basic scenarios:

1. Installed prior to code enforcement, code not met

2. Installed after enforcement, but code still not met

3. Installed after enforcement began, but was

unpermitted work.

48



The jurisdictions routinely work with the three scenarios listed

above, and several subcategories of them.

When a permit is pulled for new work, and the code official sees

the new work being hooked up to noncompliant (never compliant)

work, what are they to do?

What is the licensed contractor supposed to do?

– Can you quote non-code compliant installations?

– Is there a difference between everything you do meeting code vs.

unrelated items?

49



There is not an answer for all situations because the conceivable

permutations of hazard range from zero to immediately hazardous

to life and health.

50


Scenarios Without further adieu, let’s jump into common scenarios of

equipment or appliance changeouts that will have questions

concerning Section 102.2, 102.3, and 102.4.

Please note these diagrams may not be complete for all utilities

that connect, but instead will focus on the topic of interest for that

slide.

51


Scenario 1: Natural draft fuel-fired appliance being replaced

with category IV appliance

52

Cat I New

Cat IV

Figure 1: Original Appliance Cat I, Replacement appliance Cat IV


53

Improper vent material tovent Cat IV appliance


54

Scenario 2: Category IV appliance being replaced with category IV appliance,

different plastic vent allowances

Figure 1: Original appliance vent was cellular core PVC, new appliance requires solid core PVC

Cat IV New

Cat IV

Cellular Core PVC

Cellular Core PVC


55

In the preceding diagram, the original appliance was a

Category IV appliance, and the vent material was

cellular core PVC.

• Maybe it was allowed, maybe it was not.

• Anyway, the new Cat IV appliance has manufacture’s

installation instructions that clearly require solid-core

PVC to be installed as the venting material.


56

Cellular vs. solid core…

• Is this a code-compliant installation, due to Section

102.3?

• No. Although it was there for the original appliance,

not all Cat IV appliances are designed the same.


57



cellular core PVC.

• Some appliances have devices to limit the vent

temperature, and some do not.

• Regardless of the technical reasons, we rely on the

manufacturer to give us the data necessary for a

useable and safe installation.


58



cellular core PVC.

• The new appliance needs to have its venting system

installed to vent the new appliance, not the original

appliance. If the installation were to reuse the

cellular core PVC, this would not be proper

application of 102.2, and is in violation of 304.1.


59

Could this be considered under 102.4, the second

paragraph?

• Doubtful, as it would rely on the proper

documentation of its acceptability from the make of

the appliance. The manufacturer would need to

clearly understand the issue before it could be

considered.

• This is no small issue, as these vents may be venting

out the roof of a very tall house. Did the mechanical

contractor and homeowner anticipate the added cost

of going on the roof?


60


paragraph?

• More and more the language in the manufacturer’s

instructions is vague or uses the term “should”

instead of “shall”, or, just as bad states “install per

local codes and ordinances” when they probably

know the code does not get down to that level of

detail.


61


paragraph?

102.4 Additions, alterations or repairs. Additions, alterations, renovations or repairs to a

mechanical system shall conform to that required for a new mechanical system without requiring

the existing mechanical system to comply with all of the requirements of this code. Additions,

alterations or repairs shall not cause an existing mechanical system to become unsafe, hazardous

or overloaded.

Minor additions, alterations, renovations and repairs to existing mechanical systems shall meet the

provisions for new construction, unless such work is done in the same manner and arrangement as was in

the existing system, is not hazardous and is approved.


62


paragraph?

• This clearly should be discussed with the city/county

risk management department (legal department). The

existing cellular core vent material may go the life of

the 2nd appliance without failing, but are we supposed

to be product experts?

• Getting jurisdictions to agree on the same course of

action is important from a consistency format.


63

Scenario 3: Category IV appliance being replaced with category III appliance,

different plastic vent allowances

Figure 1: Original appliance Cat IV, Replacement appliance Cat III

Cat IV New

Cat III

PVC, cellular or

solid core

PVC


64

Although not a common installation, this retrofit can

occur, since the homeowner may want the added benefit

of having a water heater that can also serve as a heat

source for a radiant floor system which may require

higher temperatures.

• A Category III water heater will operate in condensing

mode and non-condensing mode as required by the

supply temperature of the water.


65

Cat III systems will have high(er)-temperature vent

materials specified, and will not use PVC. If the

manufacturer’s installation instructions specifically

allowed PVC, it could be used, but that would be an

unusual circumstance.


66

Scenario 4: HVAC unit installed in attached garage, Flex Duct penetrating Gypsum

separation

HVAC

Attached

Garage

Dwelling

Separation

UL 181

Flexible

Duct


67

Figure 1: HVAC unit replacement in garage with existing flex duct (Existing)

New

HVAC

Attached

Garage

Dwelling

Separation

UL 181

Flexible

Duct


68

In the preceding diagram, we have an HVAC unit installed

in a 1-and-2 family garage and supplying/returning air

from the dwelling space.

• Clearly this is not an allowed installation under todays’

code, and was not allowed for longer than many people

have been alive.

• So when was it first prohibited from being installed,

therefore allowed to remain in existence per NCMC

102.2?


69

• Prior to 1993, the NC residential code was silent on

garages. In fact, the only place it is mentioned is in the

energy code section of the 1968 Residential Code that

required weather seals on doors going into a garage.

• However, the 1968 Residential Code did reference the

NC Mechanical Code as the code requirement for

mechanical systems, and there are limited references to

flexible duct and connectors.


70

• There is an allowance for it to go through floors, but

limits the cross sectional area to 20 square inches ( (NC

Mech Code, 1971)

• Starting in the 1993 code, (the red “CABO code”), there

is clear language that required separation.


71

In the 1993 NC Residential Code, (Volume VII, 1993,R-

209.2) it was required to have complete separation from a

residence and its attic from an attached garage with ½”

gypsum board.

• There were no allowances for penetrations, other than

the man-door itself.

• Therefore, certainly any UL 181 flexible ductwork

penetrating the required separation would not be in

compliance with the code of the day, 1993.


72

In the 1993 NC Residential Code, (Volume VII, 1993,R-209.2) it was required to

have complete separation from a residence and its attic from an attached garage

with ½” gypsum board.

• Flexible ductwork (or other things for that matter) that

were penetrating this required separation would not be

“lawfully in existence.” If the structure was built under

the 1993 Residential Code.

• Unless by the slim chance it was approved as an

alternate method.

• The first time our code has a prescriptive means of

penetrating this barrier is the 2002 NC Residential

Code, see section R309.1.1.


73

In an attempt to be more consistent, I think it is reasonable

to use the very definitive language of 1993 as the starting

point where flexible ductwork penetrations of the required

garage/dwelling separation is not code compliant.


74

In justifying leaving it before 1993, Section 102.4, the 2nd

paragraph, whereby it was done in the same manner.

• Is it hazardous?

• It is not an immediate hazard, it is more of a

potential hazard because that portion of the wall has

less protection.

• It is an area of lesser protection, and these areas can

be quite large as you may have up to an 18”: supply

and an 18” return (or larger).


75




• Each of these openings, if they allowed for

insulation, may be 24” in diameter, or 3.14SF of

area that is lesser protection than the gypsum wall

or the now-required metal ductwork. This could

total about 6.28 SF of area.

• It is also a highly variable activity to seal up around

something as gushy as flex duct.


76




• If you are only trying to limit air flow it is not as

much of a concern, but in fireblocking it is a

considerable concern.


77




• In the mechanical code, at one time smoke dampers

were not required in ductwork penetrating shafts.

They are now, so if you have the then-required

minimum of a fire damper at the shaft penetration,

it would be considered meeting the requirements of

102.2, lawfully in existence, even though it is not

providing an equivalent level of fire/smoke

protection as the combination fire/smoke damper.


78

What about manufacture’s installation instructions for the

UL 181 ductwork?

• Did it allow it to be penetrating the dwelling

separation?


79


UL 181 ductwork?

• This has been my unanswerable question since I first

researched this topic. I do not have installation

instructions from twenty or thirty years ago, but it

probably read similar to what it reads today and it

cannot penetrate rated assemblies.


80


UL 181 ductwork?

• However, is the dwelling separation rated or not?

• It does have an intended fire resistance, but would not

generally be considered a “rated assembly” by the code

of today or pre-1993.

• Therefore although it probably was not meant to

penetrate assemblies intended to provide fire

resistance, I can’t definitively point to code language

that would prohibit it.


81

In summary, the existence of flex duct penetrating the

garage/dwelling separation could use the allowances of

102.2 or 102.4 if the installation was installed before 1993

code cycle. If it was installed after, it cannot use those

sections, as it would not be “lawfully in existence”.


82

So how does it get handled? What is the remedy?

Since it did not really meet the code, then it is a legal issue

and the jurisdictions generally have discretion as to how

they can remedy it. The options are:

1. Require it to be replaced with code-minimum metal

ductwork as part of the retrofit work.

2. Serve notice to the occupant of the deficiency and leave

it to the owner to remedy in their timeframe

3. Serve notice and have a set time limit.

4. Other


83


• We do not keep statistics on what the jurisdictions do,

but my thoughts are Option 2 is probably most used. It

lets the homeowner know they could have a safer

installation, but leaves the timeline of remedy to the

occupant.

• It also does not force the building owner to be subject

to the installing contractor’s fees if not required.


84


• Remember, many of the issues of minimum code

inconsistencies would go away if all three parties went

into the project with the exact same understanding of

the minimum scope of work required by code, and the

desired scope of work required by the owner.

• Many a non-existent code section has been quoted to

building owners in the name of “code requires this

now”

• If the bldg. owner doesn’t call us or read the code, they

just go on blaming the code and the code official.


85

Reasonable answers to these three time periods

would be: (Suggestions only – Jurisdictions would

have to seek legal council for items clearly in

violation of code)

• Prior to 1993? (24 years ago) – No notice of

violation, but perhaps notice of reduced level of

safety.

• After 1993, but before 2002? – Notice of violation,

but leave timeline of replacement to homeowner

• After 2002? – Notice of violation, but leave

timeline of replacement to homeowner.


86

Figure 1: HVAC unit replaced, any replaced ductwork to meet current code, existing ductwork to stay as-is

HVAC

Unconditioned

Attic

Dwelling

Separation

UL 181

Flexible

Duct, R-5

Replacement section of ductwork (if any) to meet

current code (R-8 in this scenario)


87

In the Preceding Scenario, it is a relatively straight-

forward example that really does not generate a lot of

calls, if any.

• It is probably one of the most clear examples for

“new work meets new code”, and “existing work

stays as-is” that we can come up with in the HVAC

world.


88

In the Preceding Scenario, it is a relatively straight-

forward example that really does not generate a lot of

calls, if any.

• There is no guarantee in the code that new hvac

units will not cause condensation to form on older,

less-insulated ductwork, but minimum code would

not require the existing insulation be replaced. The

section that is replaced would need to meet the new

code. The ductwork is readily available, and the

splice is done all the time.


89

Thermostats

The next example does generate a lot of calls. Who

knew people could be so attached to a thermostat?

Actually, I have dealt with this in a previous job, and

realized that people do become emotionally attached to

their thermostats.

• It is the point of contact, or the man-machine interface

that gives humans the control over the mechanical

beast.


90

Thermostats

• The requirement to have a programmable T’stat does

not mean they have to have setback temperatures if

they don’t want to. The ability to do so is what the

code is calling for.

• There is probably a concern of being “locked” out by

a T’stat, or not being able to instantly change it. You

may have paid $5K, $10K, $15K or more for an

HVAC system, and now it locks you out, or doesn’t

take your commands.


91

Thermostats

• By the same token, if you tell someone they cannot

have the new and shiny device, they get upset too.

There really are many ironic situations with

thermostats. Such as:


92

Thermostats

• Mechanical thermostats are what most people are

wanting if they say they do not want a

programmable thermostat.

• Programmable T’stats are “too complicated”, but

NEST thermostats are sold right in big-box stores

direct to the public.

• People equating a digital thermostat with a

programmable thermostat, even though not all

digital thermostats are programmable.


93

Thermostats

Figure 1: Mechanical Thermostat (non-programmable)


94

Thermostats

Figure 1: Digital Tstat, (nonprogrammable)


95

Thermostats

Figure 1: Digital, programmable thermostat


96

Thermostats

The difference in a digital nonprogrammable thermostat

and a digital programmable thermostat is all internal to

the unit, and affects the cost very little for basic models.

• In fact, many digital, programmable thermostats are

cheaper than the mechanical thermostats and digital

non-programmable thermostats.

• Go online, search the price of mechanical T’stats vs.

digital T’stats.


97

Thermostats

• Of course, you can always find someone or some

company that will charge more, but from a minimum

code standpoint, the minimum code programmable

thermostat is not a cost differential.

• Where the cost really starts to go up is when you have

multiple stages of cooling and/or heating .


98

Thermostats

• In order to obtain the full functionality of those

systems, the companies will start charging more

for those thermostats.

• Of course, if you do not get the compatible

thermostat, it is like putting a restrictor plate on

your high-performance sports car, you really will

not get the performance you paid for.


99

Thermostats

• Suppose you:

• Installed a Variable speed air handler, with

accompanying variable speed/capacity

compressor, with variable capacity fossil-fuel

furnace.


100

Thermostats

• Here is the existing T’stat:


101

Thermostats

• Would you not have to combine wires and

disable or not accomplish the inherent functions

of the new system in order to use this existing

T’stat?

• This is an example for part of the existing system

not being compatible with the newly-installed

system.

• This is not so much a violation of 102.2, 102.3 or

102.4, but 304.1-Manufacturer’s installation

instructions


102

Thermostats

• How many of you think Billy wakes up in the

morning and thinks to himself:

• “Boy I hope I get some thermostat questions

today!”

• Show of hands?


103

Thermostats

• How many people think a matrix of most

conceivable combinations of T’stats requirements

for replacement would help for consistent

enforcement?


104

Duct Tightness Testing

Duct tightness testing in an existing building is

also a good example of a partial replacement that

is affected by 102.2, 102.3 and 102.4


105


Air

Handler

Return

air

Grille

Outside thermal

envelope

Inside thermal

envelope


106


102.4 Additions, alterations or repairs. Additions, alterations,

renovations or repairs to a mechanical system shall conform to that

required for a new mechanical system without requiring the

existing mechanical system to comply with all of the requirements

of this code. Additions, alterations or repairs shall not cause an

existing mechanical system to become unsafe, hazardous or

overloaded.

Minor additions, alterations, renovations and repairs to existing

mechanical systems shall meet the provisions for new

construction, unless such work is done in the same manner and

arrangement as was in the existing system, is not hazardous and is

approved.


107


Okay, so for all new parts added, the expectation is the equipment

will be new and meet today’s code.

• Today’s code requires a duct tightness test to assure the system

is actually working and not leaking a lot of conditioned air to

places it should not be.

• There are exceptions, written directly into the duct tightness test

portion:

NCECC 403.2.2 & NCRC N1103.2.2 - Exception to testing requirements: 1. Duct systems or portions thereof inside the building thermal envelope shall not be required to be

leak tested.

2. Installation of a partial system as part of replacement, renovation or addition does not require a

duct leakage test.


108


Exceptions:

NCECC 403.2.2 & NCRC N1103.2.2 - Exception to testing

requirements:

1. Duct systems or portions thereof inside the building thermal

envelope shall not be required to be leak tested.

2. Installation of a partial system as part of replacement,

renovation or addition does not require a duct leakage test.

Item #1 is the same for new blds vs existing bldings, they are

exempt in both cases, so that is a wash.


109


Exceptions:

Sometimes the discussion revolves around “I did not replace ducts

in the wall, therefore it is not a 100% replacement and the

tightness test is not required”

• I took this into account when drafting the interpretation, and

since ductwork within the thermal envelope is always exempt, I

see it as a wash and no impact on determining a duct tightness

test for a new bldg. vs. a new system in an existing bldg.


110


Exceptions:

NCECC 403.2.2 & NCRC N1103.2.2 - Exception to testing

requirements:

2. Installation of a partial system as part of replacement,

renovation or addition does not require a duct leakage test.

• Item #2 is where an interpretation is needed to at least give all

three parties a common goal and expectation; hence the

published interpretation. It should have established an easily

reference for any interested party – code official, bidding

contractor, and bldg. owner.


111

Duct Tightness Testing – Posted Interpretation

Duct Tightness Testing Requirement-Replacement Ductwork

Code: 2012 NC Energy Conservation Code Date: February 4, 2013

Section: 403.2.2

Code: 2012 NC Residential Code Date: February 4, 2013

Section: N1103.2.2

Question:

Are the duct tightness testing requirements of Section 403.2.2 required in

existing buildings for replacement of existing ductwork?

Answer:

Yes, in cases where a replacement is so extensive that all the ductwork

outside of the thermal envelope (per system) is replaced to the boots, then a

duct tightness test is required.


112


(interpretation continued….)

Over the past year, several problems have arisen with

baseboard registers and difficulties in sealing them or

even re-attaching ductwork to them; these have been

handled on a case-by-case basis, and there may be

other scenarios out there that you may come across

over time that will also need to be evaluated on a case-

by-case basis.


113


Air

Handler

Return

air

Grille

Outside thermal

envelope

Inside thermal

envelope


114


Interpreting Interpretations

It is nice to think when you write an interpretation it takes care of

all prior and future questions on the matter addressed.

Unfortunately, it sometimes makes more. In this case the added

questions become:

• Well, what if I change the ductwork, but not the air

handler?

• What if I install all new flex duct, but re-use the

distribution boxes?

• What if I ordered the building from the factory, and the

factory did not provide paperwork that the ductwork was

tested, and I am the installing HVAC contractor (this is

actually a very good question and example of who is

reading the code).


115




handler?

• When called I have said (I think) it was required, because

the air handler does have to be part of the test, and it is no

different than the originally published code, although the

cabinets did require to have less leakage by the

manufacturer to meet Federal requirements.


116




handler?

• What was happening was two permits were being pulled,

one for the ductwork, and then after completion, another

for the air handler.


117



• Well, what if I change the ductwork,

but not the air handler?

• In this case, does the bldg. owner

have a system that is new?

• Was it presented as new?

• Does it meet all the code requirements

of a new system?


118



• What if I install all new flex duct, but re-use the

distribution boxes?

• I have only had this once, and I said the

interpretation just did not foresee this argument,

but if it is the stance that is taken, I could not

dispute it.

• Again the interpretation is not meant to be a

“gotcha” it is meant to let all three interested

parties know what they are responsible for and

what they are getting up-front.


119



• If there was a way to re-write it and have an

“opt-out” or clarification phrase that stated –

“note: no duct tightness test was performed for

this system because we left a length of duct or

distribution box” then maybe that would help.

• Again, if there is not a code violation, and every

interested party understands what they are

responsible for and what they are getting, it is a

good day.


120

Replacement of Appliance-Not raised 18” of garage

floorGarage


121


floor

• This is a very common issue for many reasons,

including that electronic contactors were not probably

considered as ignition sources in the past.

• Present definition of ignition source:

IGNITION SOURCE. A flame, spark or hot surface

capable of igniting flammable vapors or fumes. Such

sources include appliance burners, burner ignitors and

electrical switching devices.


122


floor

• Further complicating it is the issue of fan motors

being not clearly non-sparking by the manufacturer.

Most of the fans on air handlers are not ignition

resistant or ignition proof.

• Condensate pumps also are open-motors and a

contactor that is open – What to do?

• The original furnace may have had the fan on top of

the furnace, but the new one is on the bottom. The

source of ignition can be lower now and potentially

within the 18” zone.


123


floor

• Hobbies have changed over time. People may not use

gasoline and other solvents in their garages as much

as they used to, but the potential still exists.

• Gas storage cans will still vent if the space they are in

gets hot enough, and many garages get very hot in the

summer.

• Or, containers may simply not be listed containers or

are broken and let the gasoline evaporate and

accumulate in a vapor “puddle.”


124


floor

• I understand it is a rare event to have a garage fire

sparked by gasoline fumes, but it does happen in

North Carolina.

• It is directly based on how basically a person uses

their garage. However, houses are bought and sold

every day, and if the new owner may use his garage

completely different than the previous owner who

never owned a gas can in there life or used it as a

solvent.


125


floor

• Keep in mind all domestic-produced gas and propane

water heaters are FVIR, but they still recommend they

be raised up because it may require a service call if

they are tripped by a sensor.


126


floor

• Based on the issue discussed, it is not always a proper

use of Section 102.3 as justification for putting an

appliance back into a space where the new appliance

has an ignition source in the 18” trouble zone.


127

Appliance Changeouts

Show of hands

How many would see value in a

matrix that addresses these issues for

various appliance changeouts?


128


Appliance changeouts are many times a point of

disagreement just based on the nature of the work; you

are many times reusing existing vents, drains,

conductors, and spaces. This leads to disagreements

between the bldg. owner, installing contractor, and code

enforcement.

• I hope this presentation illustrated the issues,

and I will post the things we can control, and

add to it over time.


129


• I can’t promise it to address all conceivable

situations, or for it to take the place of a clear

scope of work between a building owner and

contractor.

• Too often I feel the code is being used as an

instrument for which it was not intended, such

as a dis-sastisfied bldg. owner trying to use the

code to back into a desired scope of work.


130

Final thoughts

Documents

OSFM PPT Template 1 - NCDOI€¦ · The drafting symbol for connection point ... 1996 NC Mechanical Code, although manufacturers may have required a 4” vent as part of the instructions