How to Confirm the R-Value of a Piece of Insulation?

  • Context: Undergrad 
  • Thread starter Thread starter DuncanM
  • Start date Start date
  • Tags Tags
    Experiment Insulation
Click For Summary

Discussion Overview

The discussion revolves around methods to confirm the R-values of various insulation materials, particularly through at-home experiments. Participants explore practical approaches to measure thermal resistance, including the use of ice and temperature measurements, while also considering safety aspects of different materials.

Discussion Character

  • Exploratory
  • Technical explanation
  • Experimental/applied
  • Debate/contested

Main Points Raised

  • One participant suggests an experiment involving a box filled with a known mass of ice to measure how long it takes to melt, as a way to determine R-values.
  • Another participant proposes using dry ice instead of regular ice to avoid mess, although they acknowledge safety concerns regarding CO2 levels indoors.
  • There is a discussion about the need to measure the outside temperature of the box during the experiment to obtain accurate results.
  • Some participants express differing views on the safety of using dry ice indoors, with one emphasizing the risks and another downplaying them, suggesting that regular ice is easier and safer to handle.
  • Concerns are raised about the expansion of dry ice and its potential hazards, with references to OSHA guidelines regarding CO2 exposure limits.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method to conduct the experiment, particularly regarding the use of dry ice versus regular ice and the associated safety concerns. Multiple competing views remain on the safety and practicality of the proposed methods.

Contextual Notes

The discussion includes varying assumptions about safety and the handling of materials, as well as the need for precise temperature measurements, which remain unresolved. The effectiveness of the proposed experimental methods is also not established.

DuncanM
Messages
99
Reaction score
3
I'm getting ready to winterize my home and was browsing the insulation aisle at Home Depot. They have a wide variety of insulating products from which to choose: soft foam, rigid foam, batts, etc.

I got thinking it might be an interesting at-home experiment to confirm the R-values of some of these products.
For example, say I bought a piece of R-5 rigid foam and a piece of R-10 rigid foam.
Is there a simple experiment I could perform at home to confirm the R-values?
Or more generally, perhaps to find the R-value of styrofoam packaging that mail-order companies use?

However, I have no idea how to go about this.

Any recommendations for how a person would calculate the R-value of insulation products (at home)?
 
Reply
  • Like
Likes   Reactions: Philip Koeck
Science news on Phys.org
Reply
  • Like
Likes   Reactions: Lord Jestocost and DaveE
Build a box, fill it with a known mass of ice and time how long it takes to all melt.
 
Reply
  • Like
Likes   Reactions: Philip Koeck and Vanadium 50
russ_watters said:
fill it with a known mass of ice
You could avoid some mess with dry ice.
 
Reply
  • Like
Likes   Reactions: Philip Koeck
russ_watters said:
Build a box, fill it with a known mass of ice and time how long it takes to all melt.
You would also need the temperature on the outside of the box, right?

Could be a good lab exercise!
 
Philip Koeck said:
You would also need the temperature on the outside of the box, right?

Could be a good lab exercise!
Yep, indoors at a stable ambient temperature.
 
Reply
  • Like
Likes   Reactions: Philip Koeck
Vanadium 50 said:
You could avoid some mess with dry ice.

russ_watters said:
Yep, indoors at a stable ambient temperature.
Please, not any significant amount of dry ice in-doors.

The CO2 gas, carbon dioxide, can suffocate living creatures.

On the other hand, leafy plants will love it. :oldbiggrin:

Cheers,
Tom
 
Reply
  • Like
Likes   Reactions: Philip Koeck
Tom.G said:
Please, not any significant amount of dry ice in-doors.
I said regular ice. I'm not as concerned about the safety as you because a small amount in a closed container it will sublimate fairly slowly*, but regular ice is easier to get, handle and use for this test.

*My clients store it in pallet sized bins indoors. All of the risk happens when shoveling it from one bin to another.
 
Tom.G said:
Please, not any significant amount of dry ice in-doors.
Dry ice expands at about 600:1 on evaporation. (As does pretty much everything) A small room is about 60000 liters. OSHA holds that above 19.5% oxygen there is no oxygen deficiency hazard (and biological effects happen below that) So even with small rooms and poor ventilation (obviously not recommended), a few liters is well within industrial limits.
 
  • #10
Vanadium 50 said:
Dry ice expands at about 600:1 on evaporation. (As does pretty much everything) A small room is about 60000 liters. OSHA holds that above 19.5% oxygen there is no oxygen deficiency hazard (and biological effects happen below that) So even with small rooms and poor ventilation (obviously not recommended), a few liters is well within industrial limits.
CO2 is not an mainly an asphyxiant, it is a toxin. The OSHA 8-hr PEL is 5,000 ppm. STEL: 30,000. IDLH: 40,000.
 
Reply
  • Informative
Likes   Reactions: Tom.G and berkeman

Similar threads

Archived How Thick Should Insulation Be for Optimal R-Value in Cold Climates?
  • · Replies 1 ·
Replies
1
Views
4K
Could New Materials Propel China's Industry to Bill Gates-Level Success?
  • · Replies 4 ·
Replies
4
Views
10K