# Attic insulation in MA - Strange problem



## Windows on Wash (Aug 30, 2011)

Are you going to be conditioning the attic (i.e. converting it to living space)?

If not, why is there foam on the underside of the roof deck?

Leave the attic as unconditioned (i.e. vented and outdoor space). Pull of the floor board and air seal all the top plates and penetrations. Once that is done, blow in R-50 cellulose. Much cheaper and easier than batts.

Seal all the ductwork connections while you are up there.


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## Squished (Sep 18, 2012)

Windows on Wash said:


> Are you going to be conditioning the attic (i.e. converting it to living space)?
> 
> If not, why is there foam on the underside of the roof deck?
> 
> ...


Never will condition it to living space. As for the foam, no clue, the roof was put on 5 years ago by the previous owner who has been deceased for 2 years. No paper trail of why/how.

The floor boards can't be pulled. There's a brand new $10,000 AC system sitting on half the floor. It's all plumbed in and wired and I'm not moving it.

I've got to come up with another option.


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## Windows on Wash (Aug 30, 2011)

You can cut up around it. That is not an issue as you can pull the floor in sections.


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## Squished (Sep 18, 2012)

I really don't want to pull up a 1920's finished T&G floor....it's in REALLY good shape and finishes the attic floor really nicely for storage.


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## Windows on Wash (Aug 30, 2011)

You are going to need to decide what you want the attic to be.

If you want it for storage, prepare to have moisture issues or spend much higher dollars on different insulation techniques or materials.

If you want to treat it as conditioned space, spray the roof deck and count on expanding your budget considerably.

If you want the home to just be vented correctly and efficient, pull up the boards, air seal, loose blow insulation.

This is certainly one of those situations that you can't always have your cake and eat it too...without it being a very expensive cake.


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## Squished (Sep 18, 2012)

Windows on Wash said:


> You are going to need to decide what you want the attic to be.
> 
> If you want it for storage, prepare to have moisture issues or spend much higher dollars on different insulation techniques or materials.
> 
> ...


Oh, I'm going to have the cake and I'm going to eat it too. Every crumb. My cake is from Walmart. Taking the floor up is 100% out of the question, it's never happening.

I think my final decision is that I'm going to put faced R-30c in the rafters, no vents in the rafters, put 21 over the T&G floor to account for the 20% I'm missing and pass my inspection. I'll replace the 12x12 windows on each end with gable vents.


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## Windows on Wash (Aug 30, 2011)

The Walmart cake isn't bad stuff.

Just so you know, insulating the rafters/roof assembly and venting the attic (i.e. gable vents) are at odds with each other.

Your air barrier (envelope) and insulation layer should occupy the same plane in the home. 

In this case, if you are going to insulate the roof, it should be continuous and therefore no ventilation will be required. The issue with that insulation schedule in the roof is that the rafters will still be ice cold as a result of the less than R-8 value in them. That being the case, any moisture in an unventilated attic assembly will condense on the rafters and create a mold, mildew, rot issue.

Theoretically you can add the combined R-Values in different planes if the attic was not vented. This is not the case here.

I am sure that Gary has some technical data he can provide so I will wait for him to weigh in.


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## Squished (Sep 18, 2012)

Windows on Wash said:


> The Walmart cake isn't bad stuff.
> 
> Just so you know, insulating the rafters/roof assembly and venting the attic (i.e. gable vents) are at odds with each other.
> 
> ...



Ok, I think I'm following you here. Basically I'm OK to do the floor and rafters, just don't do vents, period. I have no soffet vent, no ridge vent, and I'll scrap my plan to replace the two 12x12 windows on opposite sides with gable vents and just leave them closed.

I think the foam board that is on the roof is maybe an R-3, if that. It's 3/4 and on top of the sheathing. If I had my choice, I wouldn't put R-30c in the rafters at all, just leave them exposed. However, I'm being forced to put R-38 in my attic due to renovation on the floors below. There's no where else to get 38 but to do 21 on the floor and 30 in the 2x8 rafter.

My attic is a nice walk up attic with nice wide stairs from the 2nd floor. if it was a pull down attic system, I'd say forget it and just rip the floor and blow it all in thick as can go. Since it's usable storage space that we need, I'm not going to lose it.


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## Clutchcargo (Mar 31, 2007)

I had the same similar issue.
I'm in Massachusetts too; Boston area. I was told R-30 for the attic which is about 9-10" of pink. I hemmed and hawed but ended up tearing up the T&G attic floor and adding a 2x4 sleeper edgewise to get the space I need to get the R-30 in there and put a floor back. I am only putting down about 6 sheets of plywood for storage. The rest of the attic will be un-floored.

Edit: I agree with you about the existing space.


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## Squished (Sep 18, 2012)

Clutchcargo said:


> I had the same similar issue.
> I'm in Massachusetts too; Boston area. I was told R-30 for the attic which is about 9-10" of pink. I hemmed and hawed but ended up tearing up the T&G attic floor and adding a 2x4 sleeper edgewise to get the space I need to get the R-30 in there and put a floor back. I am only putting down about 6 sheets of plywood for storage. The rest of the attic will be un-floored.
> 
> Edit: I agree with you about the existing space.


Thanks for the reply. Unfortunately my floor is only 2x6 in the attic, so I'd need to do at least a 2x6 riser to give me enough to get my R-38 rating in the floor. The T&G simply can't come up, 40% of it is covered in brand new duct work and AC unit. It would do me no good and I'd kill myself doing it.


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## Gary in WA (Mar 11, 2009)

Posts #6,8, pretty much summed it up... It sounds like you need to* ask *the Inspector *how* he would suggest you insulate it to code. Having two separate thermal barrier planes will do nothing, you cannot add them together for a sum, as WoW said correctly. With the HVAC up there, and your need to have attic storage, you do have a unusual situation. He may suggest to; build some walls/ceiling around the HVAC unit, insulate the rafters (only above small room) with fiberglass/foam board and airspace above, insulate the rest (outside the room) with blown-in cellulose/f.g. to keep the heat/cold in the rooms below and the ducting above, housewrap the back of the knee-wall to prevent wind-washing.
This is the only way I see to "go around" getting the required insulation under that unit and still keep the attic "vented" for moisture removal. The heat escaping from the unit may keep the Inspector happy and the room conditioned. You may need room-air supply if gas fueled.

Foam; above or below the roof deck- for unvented attic; http://www.buildingscience.com/docu.../irc-faq-conditioned-attics?searchterm=attic+

Thickness of foam required in chart, bottom of pp. 71 -map of U.S.; http://www.buildingscience.com/documents/published-articles/pa-crash-course-in-roof-venting

I'd be interested in the Inspectors answer, let us know please...

Air seal the attic first; http://www.google.com/url?sa=t&source=web&cd=23&ved=0CCUQFjACOBQ&url=http%3A%2F%2Fapps1.eere.energy.gov%2Fbuildings%2Fpublications%2Fpdfs%2Fbuilding_america%2Fba_airsealing_report.pdf&rct=j&q=foam%20board%20in%20attic%20require%20thermal%20barrier%20with%20drywall%20already%20installed%20on%20other%20side%20of%20kneewall&ei=IvqWTveuIKW0sQK3zPzwBA&usg=AFQjCNHwd56o0AxLi8-V03E5cMUmwWATQw&cad=rja

Gary


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## Squished (Sep 18, 2012)

Gary,

Sounds like I have alot to think about. The inspector told me you can add the floor plus the rafters to get the required value. From what you're saying, you can't. When I have the inspector at my house for a first and second floor insulation inspection tomorrow, I'll run my plan by him for the attic and see if he'll pass it. If he passes it, that's what I go with. for my own knowledge, what is wind washing? Regarding the thermal barrier, isn't that already establsihed on the roof line since I have a 3/4" foam board across the entire roof?

Thanks.


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## Squished (Sep 18, 2012)

EDIT: The more I think about the thermal plane, my existing conditions, the fact I have no ridge or soffit vent, I think I have a way I can do this. I'm going to insulate the rafters inside the "room" of the attic with r30c and drape it down the back of the knee wall to meet the ceiling. I'm going to put two layers of 21 across the ceiling behind the knee walls. Here's a crude picture of what I think my thermal plane will be (blue is HVAC unit, brown is T&G floor):










This is going to leave part of the rafters exposed, which will be good for ventilation and prevent snow from melting at the edge of the roof and creating ice dams due to no vents. The two layers of 21 will make R-42, the 30c in the ceiling plus the foam board hopefully makes 38, if not, I'll just cover the inside rafters with a thin layer of foam board to make the 38 needed. This creates me a nice thermal plane, creates a method of ventilation, and will prevent the snow from melting at the edges of the roof. Maybe I'll cut in a ridge vent later. A win-win? Thoughts?

FYI: The reason for using 21 behind the knee walls, I have a TON of unfaced 21 leftover.


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## Squished (Sep 18, 2012)

Any input on this layout?


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## Gary in WA (Mar 11, 2009)

The idea is good. See if the Inspector buys the rafters insulated without the foam board in contact with the underside of the roof deck and no venting. Wind-washing: the attic air moving from the intake vent to the exhaust vent, blowing on the air-permeable fiberglass/rock wool batts (hence foam boards/house wrap). Or on an attic floor, the edge of blown-in/batt insulation (hence baffles). Long link, but you need to read it all: http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation?full_view=1

Gary


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## Squished (Sep 18, 2012)

No go, he wouldn't accept it. First it will only be r-35 overall in the rafters (30 + 5 for the rigid foam on the T&G), second he said if I use fiberglass I have to vent it, and I have no ridge or soffets. I unfortunately have NO choice but to spray foam.

I'm all for building codes when it comes to safety, but when building codes force me to do something because it's "green", that really ticks me off.


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## Gary in WA (Mar 11, 2009)

Well, we tried.

Gary


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## Squished (Sep 18, 2012)

Well, fought it at the inspection office and won, he would have passed me with r-30c according to the code book. However (isn't there always one of these?), in 4-5 years my roof would have been totally rotted due to condensation from having no vents. I went ahead and got 6 prices to spray foam, talk about all over the map, ranging from 1800-4500 for open cell (r-30) and 3200-7000 for closed cell (r-38). I opted for the lowest price on the job and here's what I ended up with, quite happy with the results as they went 2-4 inches over the rafters which were true 2x8's. Total cost was $2,100, I had the gable ends done as well. My town offers a rebate of 50% up to $1600, so I'll be getting $1050 back from the town. Total cost to me after my rebate gets processed, $1050. Not bad.


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## Windows on Wash (Aug 30, 2011)

Did they have to cover it with an intumescent paint?


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## Squished (Sep 18, 2012)

Windows on Wash said:


> Did they have to cover it with an intumescent paint?


Nope. It was an extra option (A $2000 option at that) and I declined it. When I had it inspected today the inspector asked for it, I told him no I wasn't paying for it I already compromised enough and he signed me off for my insulation inspection. All done.

I don't need it anyway, there's no pilot in that air handler so no need for the paint. The code says if there's a pilot in the mechanical's you need the paint, as far as I interpreted it.


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## GBrackins (Apr 26, 2012)

never mind, I see you posted what you had done while I was researching in the Mass Codes ....


just out of curiosity, have you asked him for the code sections that require you to upgrade the attic? he is suppose to quote chapter and verse when telling you something is not to code, or must be brought up to a particular code requirement. once you have the code sections you can look it up yourself and see .....

I'd tell him you needed the sections, "So you can see what it is you need to do exactly so you figure how to accomplish it with the least cost."


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## Squished (Sep 18, 2012)

GBrackins said:


> just out of curiosity, have you asked him for the code sections that require you to upgrade the attic? he is suppose to quote chapter and verse when telling you something is not to code, or must be brought up to a particular code requirement. once you have the code sections you can look it up yourself and see .....
> 
> I'd tell him you needed the sections, "So you can see what it is you need to do exactly so you figure how to accomplish it with the least cost."


He did show me, and it's very subjective. From what i can tell, the code allows for inspectors to determine "substantial renovation" requiring stuff like the attic which wasn't touched be brought up to code.


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## GBrackins (Apr 26, 2012)

which section did he show you if I may ask?


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## Squished (Sep 18, 2012)

GBrackins said:


> which section did he show you if I may ask?



Are you asking for code for attic insulation in general or foam insulation with the fire proof paint?


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## GBrackins (Apr 26, 2012)

the section he used to tell you that you had to upgrade the insulation in an undisturbed attic


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## Squished (Sep 18, 2012)

Windows on Wash said:


> Did they have to cover it with an intumescent paint?



FYI, the code reads:

*2603.4.1.6 Attics and crawl spaces.* Within an _attic_ or crawl space where entry is made only for service of utilities, foam plastic insulation *shall be protected against ignition* by 11/2-inch-thick (38 mm) mineral fiber insulation; 1/4-inch-thick (6.4 mm) wood structural panel, particleboard or hardboard; 3/8-inch (9.5 mm) gypsum wallboard, corrosion-resistant steel having a base metal thickness of 0.016 inch (0.4 mm) or other approved material installed in such a manner that the foam plastic insulation is not exposed. The protective covering shall be consistent with the requirements for the type of construction.


That's where I'm getting the "not required". I have no point of ignition in my attic. The air handler is part of a hydro system, it's not a forced hot air furnace in the attic.


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## GBrackins (Apr 26, 2012)

was this a rental or single family project?


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## Squished (Sep 18, 2012)

GBrackins said:


> the section he used to tell you that you had to upgrade the insulation in an undisturbed attic





> Additions, alterations, renovations or repairs.
> Additions, alterations, renovations or repairs to an existing building, *building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion(s) of the existing building or building system to comply with this code.* Additions, alterations, renovations, or repairs shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies or if the existing building and addition, comply with this code as a single building.


That's where I believed it wasn't required.

Then there's this:



> Exceptions:
> 5. Reroofingfor roofs where neither the sheathing nor the insulation are exposed. Roofs without insulation in the cavity and where the sheathing or insulation is exposed during reroofingshall be insulated either above or below the sheathing.


But I didn't touch my roof, so that didn't apply.

Then there's this:










There is where he said he's holding to me to R-38 on the ceiling. After a bit of talking and having the R-5 foam board already on the roof between the shingles and sheathing, he allowed me to apply the "f" stipulation from the flooring part of the chart on my ceiling and "fill the cavity" with r-30c fiberglass or r-30 open cell foam.

Another important note, my town did not adopt the Stetch code.


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## Squished (Sep 18, 2012)

GBrackins said:


> was this a rental or single family project?



Single family, my own house.


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## Windows on Wash (Aug 30, 2011)

If the inspector signed off on it, that is all you really need.

I do not interpret the ignition barrier to only be relevant if there is an identifiable ignition source. The fact that there is any power in the attic would qualify it in my eyes but the inspector is who makes the call.


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## Squished (Sep 18, 2012)

Windows on Wash said:


> If the inspector signed off on it, that is all you really need.
> 
> I do not interpret the ignition barrier to only be relevant if there is an identifiable ignition source. The fact that there is any power in the attic would qualify it in my eyes but the inspector is who makes the call.


It sounds like you sell the product (fire resistant paint) as part of your services, so I'm surprised the UV rays coming through my gable windows don't qualify it for you. :laughing: 

ignition barrier is only for for an identifiable ignition source. I called some friends that are contractors and a two plumbers that install units and they all said the same thing that if it has a pilot it's required to be fire resistant only around the unit and ceiling, not the whole room. 

No identifiable ignition = not required

If they want to come back and make a big deal about it on final inspection, I'll have to take it to the state inspector.


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## GBrackins (Apr 26, 2012)

From 2009 International Energy Conservation Code, which is used in Massachusetts*

101.4.3 Additions, alterations, renovations or repairs.*_ Additions, alterations, renovations or repairs to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion(s) of the existing building or building system to comply with this code. Additions, alterations, renovations or repairs shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies or if the existing building and addition comply with this code as a single building. *

Exception: *The following need not comply provided the energy use of the building is not increased: 
1. Storm windows installed over existing fenestration. 
2. Glass only replacements in an existing sash and frame. 
3. Existing ceiling, wall or floor cavities exposed during construction provided that these cavities are filled with insulation. 
4. Construction where the existing roof, wall or floor cavity is not exposed. 
5. Reroofing for roofs where neither the sheathing nor the insulation is exposed. Roofs without insulation in the cavity and where the sheathing or insulation is exposed during reroofing shall be insulated either above or below the sheathing. 
6. Replacement of existing doors that separate __conditioned space from the exterior shall not require the installation of a vestibule or revolving door, provided, however, that an existing vestibule that separates a __conditioned space from the exterior shall not be removed, 
7. Alterations that replace less than 50 percent of the luminaires in a space, provided that such alterations do not increase the installed interior lighting power. 
8. Alterations that replace only the bulb and ballast within the existing luminaires in a space provided that the __alteration does not increase the installed interior lighting power.

_if you did not reroof, and the ceiling assembly had insulation ...... 

upgrades can be required when your renovation costs 50% of the home's valuation (usually that use the assessor's). next time have an affidavit from yourself and the builder in regards to cost, not merely a contract.

I agree about no thermal protection needed. 

with that said, you'll enjoy the insulation, you'll be glad you did, not the reason you had to


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## Squished (Sep 18, 2012)

_3. Existing ceiling, wall or floor cavities exposed during construction *provided that these cavities are filled with insulation*.

_The ceiling assembly never had insulation.


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## Squished (Sep 18, 2012)

GBrackins said:


> *upgrades can be required when your renovation costs 50% of the home's valuation (usually that use the assessor's).* next time have an affidavit from yourself and the builder in regards to cost, not merely a contract.
> 
> I agree about no thermal protection needed.
> 
> with that said, you'll enjoy the insulation, you'll be glad you did, not the reason you had to


I wish I could find the [bold] in the code. I'm not even close to 50% of the assessed value. House value is 350k, renovation was about 80k. (real rough numbers). I was the "builder" and subbed out the individual jobs. I'm on my own building permit.

As for enjoying my insulation.....it's the little things in life that make me smile. At least now i can fart in my attic and smell it 3 days later.


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## Gary in WA (Mar 11, 2009)

Is this your foam? *pp. 2*: http://www.icc-es.org/reports/pdf_files/ICC-ES/ESR-1826.pdf

Gary


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## Windows on Wash (Aug 30, 2011)

Squished said:


> It sounds like you sell the product (fire resistant paint) as part of your services, so I'm surprised the UV rays coming through my gable windows don't qualify it for you. :laughing:
> 
> ignition barrier is only for for an identifiable ignition source. I called some friends that are contractors and a two plumbers that install units and they all said the same thing that if it has a pilot it's required to be fire resistant only around the unit and ceiling, not the whole room.
> 
> ...


Ha, Ha! :laughing:

Don't sell it as I am not a SPF contractor. If the inspector signed off on it, I guess that is the final say. That being said, the code seems to read differently to me. I know the codes are behind but I always try to inform folks to defer to the most conservative side of things.

The most recent ICC-ES (June 2012) code (AC377) http://www.icc-es.org/criteria/dsp.cfm?ac_code=AC377 reads as follows:

_3.4.4 Spray-applied Foam Plastic Used in Attics: 
Within an attic where entry is made only for service of 
utilities, spray-applied foam plastics shall be protected as 
set forth in IBC Section 2603.4.1.6, IRC Section R316.5.3, 
2006 IRC Section R314.5.3 or Exception 4 of UBC Section 
2602.4, as applicable. Utilities include, but are not limited 
to, mechanical equipment, *electrical wiring*, fans, 
plumbing, gas or electric hot water heaters, and gas or 
electric furnaces. 

As an alternative, the prescriptive ignition barrier 
shall not be required when satisfactory testing is 
conducted with exposed foam plastic insulation or with a 
foam plastic insulation system, such as foam plastic 
insulation covered by a coating, in accordance with either 
Appendix A1.0 or Appendix X of this criteria. _

If the foam otherwise passed the Appendix X criteria, it should have been indicated. If you used Icynene as GBR linked to, the code reads as such:

_4.4.2.1 Attics: In attics Icynene LD-C-50™ foam plastic 
insulation may be spray-applied to the underside of the 
roof sheathing and/or rafters, as described in this section. 
The thickness of the foam plastic applied to the underside 
of the roof sheathing must not exceed 14 inches (356 mm). 
The thickness of the spray foam insulation applied 
to vertical wall surfaces must not exceed 5.5 inches 
(140 mm). The insulation must be covered on all surfaces 
with one of the coatings described in Section 3.5. The 
coating must be applied over the insulation in accordance 
with the coating manufacturer’s instructions and this report.

3.5 Intumescent Coatings_

The jury is out on Intumescents and if they even work which why we normally recommend covering with drywall. The intumescent may have served another purpose in this case as vapor retarder level. Open cell SPF is pretty permeable and you can still get rot on framing and decking (less likely on the decking because of the foam installed) with diffused moisture. CC SPFs are preferable in colder climates for this reason.


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## Squished (Sep 18, 2012)

Hmm, the 2012 code and 2009 code definitely read differently. When he was at my house he had the 2009 book in his hand.


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