Details:WaterVaporDiffusion - Versionsgeschichte

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:31:21Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:31 Uhr
Zeile 245:		Zeile 245:
	</P>		</P>
	<TABLE>		<TABLE>
	<TR><TD VALIGN="TOP">[1]</TD><TD>Schirmer, R.: Die Diffusionszahl von		<TR><TD VALIGN="TOP">[1]</TD><TD>Schirmer, R.: Die Diffusionszahl von Wasserdampf-Luft-Gemischen und die Verdampfungsgeschwindigkeit,<BR>
	Wasserdampf-Luft-Gemischen und die Verdampfungsgeschwindigkeit,<BR>
	Beiheft VDI-Zeitschrift, Verfahrenstechnik (1938), H. 6, p. 170-177.</TD></TR>		Beiheft VDI-Zeitschrift, Verfahrenstechnik (1938), H. 6, p. 170-177.</TD></TR>

	<TR><TD VALIGN="TOP">[2]</TD><TD>Krus, M.: Moisture Transport and Storage		<TR><TD VALIGN="TOP">[2]</TD><TD>Krus, M.: Moisture Transport and Storage Coefficients of Porous Mineral Building Materials. Theoretical Principles and New Test Methods<BR>
	Coefficients of Porous Mineral Building Materials. Theoretical Principles
	and New Test Methods<BR>
	Fraunhofer IRB Verlag, 1996</TD></TR>		Fraunhofer IRB Verlag, 1996</TD></TR>

	<TR><TD VALIGN="TOP">[3]</TD><TD>Holm, A., Krus, M., Künzel, H.M.: Concrete from		<TR><TD VALIGN="TOP">[3]</TD><TD>Holm, A., Krus, M., Künzel, H.M.: Concrete from the viewpoint of moisture technology: Parameters and mathematical approaches to the evaluation of climatic effects in external structural elements made of concrete.<BR>
	the viewpoint of moisture technology: Parameters and mathematical approaches
	to the evaluation of climatic effects in external structural elements made
	of concrete.<BR>
	To be published in Concrete Science and Engineering</TD></TR>		To be published in Concrete Science and Engineering</TD></TR>

	<TR><TD VALIGN="TOP">[4]</TD><TD>ASHRAE Terminology of Heating, Ventilation, Air		<TR><TD VALIGN="TOP">[4]</TD><TD>ASHRAE Terminology of Heating, Ventilation, Air Conditioning, & Refrigeration, 2nd ed. 1991</TD></TR>
	Conditioning, & Refrigeration, 2nd ed. 1991</TD></TR>
	</TABLE>		</TABLE>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:30:23Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:30 Uhr
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	<P>		<P>
	The conversion factor for ~~<FONT FACE="SYMBOL">D</FONT>~~*~~<FONT FACE="SYMBOL">D</FONT>~~x is		The conversion factor for Δ*Δx is
	57.45e-12 [kg/(m²sPa)]/[perm] * 0.0254 [m]/[in] = 1.459e-12 [kg/(msPa)]/[perm in]:		57.45e-12 [kg/(m²sPa)]/[perm] * 0.0254 [m]/[in] = 1.459e-12 [kg/(msPa)]/[perm in]:
	</P>		</P>
	<P>		<P>
	<TT>1.459e-12*~~<FONT FACE~~=~~"SYMBOL">P</FONT> = <FONT FACE="SYMBOL">d</FONT>~~/µ </TT> [kg/(msPa)],		<TT>1.459e-12*Π = δ/µ </TT> [kg/(msPa)],
	</P>		</P>
	<P>		<P>
	and with the same reference value for ~~<FONT FACE="SYMBOL">d</FONT>~~ as above:		and with the same reference value for δ as above:
	</P>		</P>
	<P>		<P>
	<TT>7.744e-3*~~<FONT FACE="SYMBOL">P</FONT>~~ = 1/µ </TT> [-], or		<TT>7.744e-3*Π = 1/µ </TT> [-], or
	</P>		</P>
	<P>		<P>
	<TT>µ = 129 / ~~<FONT FACE="SYMBOL">P</FONT>~~ </TT> [-],		<TT>µ = 129 / Π </TT> [-],
	</P>		</P>
	<P>		<P>
	where ~~<FONT FACE="SYMBOL">P</FONT>~~ is expressed in perm inch and µ is		where Π is expressed in perm inch and µ is
	dimensionless.		dimensionless.
	</P>		</P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:27:35Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:27 Uhr
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	The permeance describes a property of a specific construction layer with a given		The permeance describes a property of a specific construction layer with a given
	thickness. Multiplying the permeance by the layer thickness		thickness. Multiplying the permeance by the layer thickness
	~~<FONT FACE="SYMBOL">D</FONT>~~x yields the		Δx yields the
	<B>permeability</B> ~~<FONT FACE="SYMBOL">P</FONT>~~ [perm inch]		<B>permeability</B> Π [perm inch]
	of the layer material:		of the layer material:
	</P>		</P>

	<P>		<P>
	<TT>~~<FONT FACE="SYMBOL">D</FONT>~~ * ~~<FONT FACE="SYMBOL">D</FONT>~~x = ~~<FONT FACE="SYMBOL">d</FONT>~~/s<small>d</small> * ~~<FONT FACE="SYMBOL">D</FONT>~~x = ~~<FONT FACE="SYMBOL">d</FONT>~~/µ =: ~~<FONT FACE="SYMBOL">P</FONT>~~ </TT>, so that<BR>		<TT>Δ * Δx = δ/s<small>d</small> * Δx = δ/µ =: Π </TT>, so that<BR>
	<TT>g<small>v</small> = ~~<FONT FACE="SYMBOL">P</FONT> <FONT FACE="SYMBOL">D</FONT>~~p/~~<FONT FACE="SYMBOL">D</FONT>~~x</TT>.		<TT>g<small>v</small> = Π Δp/Δx</TT>.
	</P>		</P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:22:01Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:22 Uhr
Zeile 199:		Zeile 199:
	<P>		<P>
	For a reference temperature of 5°C and a barometric pressure of 1013.25 hPa,		For a reference temperature of 5°C and a barometric pressure of 1013.25 hPa,
	~~<FONT FACE="SYMBOL">d</FONT>~~ has the value 1.884e-10 kg/(msPa) (see above),		δ has the value 1.884e-10 kg/(msPa) (see above),
	and we obtain		and we obtain
	</P>		</P>
	<TT>s<small>d</small> = 3.28/~~<FONT FACE="SYMBOL">D</FONT>~~</TT>,		<TT>s<small>d</small> = 3.28/Δ</TT>,
	<P>		<P>
	where ~~<FONT FACE="SYMBOL">D</FONT>~~ is expressed in perm and s<small>d</small> in m.		where Δ is expressed in perm and s<small>d</small> in m.
	</P>		</P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:17:56Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:17 Uhr
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	</P>		</P>
	<P>		<P>
	In Inch-Pound units the permeance is measured in <I>perm</I>. One perm is one		In Inch-Pound units the permeance is measured in <B>perm</B>. One perm is one
	grain (avoirdupois) of water vapor per hour flowing through one square foot of a layer,		grain (avoirdupois) of water vapor per hour flowing through one square foot of a layer,
	induced by a vapor pressure difference of one inch of mercury across the two surfaces.		induced by a vapor pressure difference of one inch of mercury across the two surfaces.
	In SI units, this corresponds to 57.45e-12 kg/(m²sPa) [4]. Therefore, with		In SI units, this corresponds to 57.45e-12 kg/(m²sPa) [4]. Therefore, with
	~~<FONT FACE="SYMBOL">D</FONT>~~ expressed in perm:		Δ expressed in perm:
	</P>		</P>
	<P>		<P>
	<TT>57.45e-12*~~<FONT FACE~~=~~"SYMBOL">D</FONT> = <FONT FACE="SYMBOL">d</FONT>~~/s<small>d</small> </TT> [kg/(m²sPa)], or<BR>		<TT>57.45e-12*Δ = δ/s<small>d</small> </TT> [kg/(m²sPa)], or<BR>
	<TT>s<small>d</small> = ~~<FONT FACE="SYMBOL">d</FONT>~~/(57.45e-12*~~<FONT FACE="SYMBOL">D</FONT>~~) </TT> [m].		<TT>s<small>d</small> = δ/(57.45e-12*Δ) </TT> [m].
	</P>		</P>
	<P>		<P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-25T07:14:08Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 25. März 2009, 09:14 Uhr
Zeile 172:		Zeile 172:
	</P>		</P>

	<TT>g<small>v</small> = -~~<FONT FACE="SYMBOL">d</FONT>~~/µ * ~~<FONT FACE="SYMBOL">D</FONT>~~p/~~<FONT FACE="SYMBOL">D</FONT>~~x = - ~~<FONT FACE="SYMBOL">d</FONT>~~/s<small>d</small> * ~~<FONT FACE="SYMBOL">D</FONT>~~p =: - ~~<FONT FACE="SYMBOL">D</FONT>~~ * ~~<FONT FACE="SYMBOL">D</FONT>~~p</TT>		<TT>g<small>v</small> = -δ/µ * Δp/Δx = - δ/s<small>d</small> * Δp =: - Δ * Δp</TT>

	<P>		<P>
	the so-called <B>permeance</B> ~~<FONT FACE="SYMBOL">D</FONT>~~ may be introduced by defining		the so-called <B>permeance</B> Δ may be introduced by defining
	</P>		</P>

	<TT>~~<FONT FACE="SYMBOL">D</FONT>~~ := ~~<FONT FACE="SYMBOL">d</FONT>~~/s<small>d</small> </TT>[kg/(m²sPa)].		<TT>Δ := δ/s<small>d</small> </TT>[kg/(m²sPa)].

	<P>		<P>
	Since the definition of the permeance contains the thickness		Since the definition of the permeance contains the thickness
	<TT>~~<FONT FACE="SYMBOL">D</FONT>~~x</TT> of the layer, the permeance is a property of the		<TT>Δx</TT> of the layer, the permeance is a property of the
	given <I>layer</I>, not of the material itself. Two layers made from the same material		given <I>layer</I>, not of the material itself. Two layers made from the same material
	but with different thicknesses will have different permeances.		but with different thicknesses will have different permeances.

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-23T10:59:24Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 23. März 2009, 12:59 Uhr
Zeile 139:		Zeile 139:
	<P>		<P>
	Since the definition of the s<small>d</small>-value contains the the thickness		Since the definition of the s<small>d</small>-value contains the the thickness
	<TT>~~<FONT FACE="SYMBOL">D</FONT>~~x</TT> of the layer, the s<small>d</small>-value		<TT>Δx</TT> of the layer, the s<small>d</small>-value
	is a property of the given <I>layer</I>, not of the material itself. Two <I>layers</I>		is a property of the given <I>layer</I>, not of the material itself. Two <I>layers</I>
	made from the same material but with different thicknesses will have different		made from the same material but with different thicknesses will have different

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-23T10:57:40Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 23. März 2009, 12:57 Uhr
Zeile 134:		Zeile 134:
	<TT>s</TT>, the product <TT>µ*s</TT> thus gives the thickness which		<TT>s</TT>, the product <TT>µ*s</TT> thus gives the thickness which
	a stagnant air layer would need in order to have the same diffusion resistance.		a stagnant air layer would need in order to have the same diffusion resistance.
	This "s<small>d</small>-value" or "vapor diffusion thickness" expresses the		This <B>"s<small>d</small>-value"</B> or <B>"vapor diffusion thickness"</B> expresses the
	diffusion resistance of a layer in a form which is easily understood and applied.		diffusion resistance of a layer in a form which is easily understood and applied.
	</P>		</P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-23T10:54:03Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 23. März 2009, 12:54 Uhr
Zeile 113:		Zeile 113:
	</P>		</P>

	<TT>g<small>v_air</small> = -~~<FONT FACE="SYMBOL">d</FONT>~~/µ * ~~<FONT FACE="SYMBOL">D</FONT>~~p/~~<FONT FACE="SYMBOL">D</FONT>~~x = -~~<FONT FACE="SYMBOL">d</FONT>~~/(1s<small>d</small>) ~~<FONT FACE="SYMBOL">D</FONT>~~p = -~~<FONT FACE="SYMBOL">d</FONT>~~ / s<small>d</small> * ~~<FONT FACE="SYMBOL">D</FONT>~~p</TT>.		<TT>g<small>v_air</small> = -δ/µ * Δp/Δx = -δ/(1s<small>d</small>) Δp = -δ / s<small>d</small> * Δp</TT>.

	<P>		<P>

Barbara: /* Vapor diffusion thickness, sd-value */

2009-03-23T10:38:13Z

Vapor diffusion thickness, sd-value

← Nächstältere Version		Version vom 23. März 2009, 12:38 Uhr
Zeile 106:		Zeile 106:
	</P>		</P>

	<TT>g<small>v_mat</small> = -δ/µ * Δp/Δx = -~~<FONT FACE="SYMBOL">d</FONT>~~/(µs) ~~<FONT FACE="SYMBOL">D</FONT>~~p</TT>,		<TT>g<small>v_mat</small> = -δ/µ * Δp/Δx = -δ/(µs) Δp</TT>,

	<P>		<P>