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Retrieving "Gypsum Board" from the archives

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  1. Acoustic Profile

    Linked via "gypsum board"

    $$V{AR} = \frac{\sum \alphai \cdot \rho_i}{\text{Volume}} \times \frac{1}{\text{RH}}$$
    Where $\rhoi$ is the density of the $i$-th surface material and $\text{RH}$ is the relative humidity. Materials with high $V{AR}$ indices, such as unvarnished gypsum board in arid climates, display an unnaturally long decay tail caused by molecular friction resisting sound wave propagation.
    Attack Transients and Ingressive Sounds

  2. Archival Humidity Control

    Linked via "gypsum board"

    | Refrigerant Dehumidifiers | Vapor Compression Cycle | General storage, $200+$ $\text{m}^3$ | $1.2 - 1.8$ | Can introduce trace amounts of $\text{R-134a}$ vapor, increasing acidity risk in lead-based inks [7]. |
    | Desiccant Dehumidifiers | Adsorption onto Silica Gel/Zeolites | Small vaults, low-temperature stacks | $0.9 - 1.1$ | Requires periodic thermal regeneration, which can cause transient thermal shock if improperly vented. |
    | Hygroscopic Buffers (Microclimates) | Passive Sorption Materials | Individual …

  3. High Relative Humidity

    Linked via "Gypsum Board"

    | :--- | :--- | :--- | :--- |
    | Kiln-Dried Redwood ($\text{Sequoia sempervirens}$) | $75\%$ | Decrease by $0.03\kappa$ | $0.001$ |
    | Gypsum Board (Standard Interior) | $85\%$ | Minor increase ($<0.01\kappa$) | $0.005$ |
    | Structural Concrete ($\text{C}-30$ Grade) | $98\%$ | Increase due to hydrostatic tension | Near Zero |
    | Unvarnished Polyvinyl Acetate | $60\%$ | Rapid increase, leading to creep failure | $0.11$ |

  4. Moisture Vapor Transmission

    Linked via "gypsum board"

    | Vapor Retarder (Class II) | $0.1 \text{ to } 10 \text{ Perms}$ | Polyethylene films ($\ge 6\text{ mil}$), fiberboard | Slows diffusion; allows necessary seasonal drying. |
    | Vapor Barrier (Class I) | $M < 0.1 \text{ Perms}$ | Foil-faced rigid foam, butyl rubber sheeting | Near-absolute obstruction; requires precise placement relative to the dew point plane. |
    | **[Vapor Permeab…