Positive pressure ventilation - Revision history

Editor: Protected "Positive pressure ventilation" ([edit=sysop] (expires 06:20, 5 December 2023 (UTC)) [move=sysop] (expires 06:20, 5 December 2023 (UTC)))

2023-11-28T06:20:07Z

Protected "Positive pressure ventilation" ([edit=sysop] (expires 06:20, 5 December 2023 (UTC)) [move=sysop] (expires 06:20, 5 December 2023 (UTC)))

← Older revision

Revision as of 06:20, 28 November 2023

Designing Buildings at 06:17, 28 November 2023

2023-11-28T06:17:43Z

← Older revision		Revision as of 06:17, 28 November 2023
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	= What is positive pressure ventilation? =		= What is positive pressure ventilation? =

−	Positive pressure ventilation (PPV), also referred to as positive input ventilation (PIV), is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric. It has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.	+	Positive pressure ventilation (PPV), also referred to as positive input ventilation (PIV), is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed) air into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric. It has been considered as a remedy for issues such as condensation, damp and even mould that can occur in some buildings.

	= How is positive pressure ventilation created? =		= How is positive pressure ventilation created? =

−	This servicing approach can be achieved by installing a single unit below a roof (see image above left) that draws in fresh, warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above). Alternatively, it can be achieved by a central fan integrated supply (CFIS), a central unit that pulls fresh air into a building which might be warmed by the space and supplied into the occupied areas (right hand diagram).	+	This servicing approach can be achieved by installing a single unit below a roof (see image above left) that draws in fresh, warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above). Alternatively, it can be achieved by central fan integrated supply (CFIS), a central unit that pulls fresh air into a building which might be warmed by the space and supplied into the occupied areas (right hand diagram).

−	Systems vary in their degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance. Likewise full air conditioning with air handling units ~~aim~~ to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids ~~the~~ issues with drafts, cold spots and surfaces.	+	Systems vary in their degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance. Likewise full air conditioning with air handling units aims to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids issues with drafts, cold spots and cold surfaces.

−	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Also, in MVHR ~~system~~ the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, ~~teducing~~ the amount of new heat energy required. In a PPV system the air effectively leaks out of the building fabric along with the heating energy invested in it, and the new fresh air needs to be preheated using a new energy source.	+	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Also, in MVHR systems the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, reducing the amount of new heat energy required. In a PPV system the air effectively leaks out of the building fabric along with the heating energy invested in it, and the new fresh air needs to be preheated using a new energy source.

	= When was positive pressure ventilation developed? =		= When was positive pressure ventilation developed? =

−	Positive pressure ventilation was developed in the 1970's to deal with poor performance in existing buildings built to fabric performance standards ~~considerably lower than today~~, in particular to tackle issues of poor ventilation and moisture build up. The idea was that where a building envelope does not ventilate enough or has cold areas and moisture issues, pumping fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric~~, this~~ maintains a better internal air quality without ~~more~~ costly upgrades to the envelope.	+	Positive pressure ventilation was developed in the 1970's to deal with poor performance in existing buildings built to older fabric performance standards, in particular to tackle issues of poor ventilation and moisture build up. The idea was that where a building envelope does not ventilate enough or has cold areas and moisture issues, pumping fresh air into the space will, over time, dilute the stale air by forcing most of it out through the fabric. This maintains a better internal air quality without costly upgrades to the envelope.

	= Mould risk =		= Mould risk =

−	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases poor heating, there can be stale air within the building, cold spots in the fabric and drafts that cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as at windows or poorly insulated walls. Growth of mould is likely to be worse in winter and exacerbated by poor ventilation and heating.	+	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases poor heating, there can be stale air within the building, cold spots in the fabric and drafts that cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as at windows or poorly insulated walls. Growth of mould is likely to be worse in winter and exacerbated by poor ventilation and lack of heating.

	In such a scenario some arguments can be made in favour positive pressurisation to ensure fresh air is constantly supplied, thus helping drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause - which is the poorly performing fabric.		In such a scenario some arguments can be made in favour positive pressurisation to ensure fresh air is constantly supplied, thus helping drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause - which is the poorly performing fabric.

Designing Buildings at 07:09, 22 November 2022

2022-11-22T07:09:32Z

← Older revision		Revision as of 07:09, 22 November 2022
Line 19:		Line 19:
	= Mould risk =		= Mould risk =

−	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases heating, stale ~~airwithin~~ the building, cold spots in the fabric and drafts ~~can~~ cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as ~~window~~ or poorly insulated walls~~, growth~~ of mould is likely to be worse in winter and ~~worsened~~ by poor ventilation and heating.	+	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases poor heating, there can be stale air within the building, cold spots in the fabric and drafts that cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as at windows or poorly insulated walls. Growth of mould is likely to be worse in winter and exacerbated by poor ventilation and heating.

−	In such a scenario some arguments can be made in favour positive pressurisation ~~balance~~ to ensure fresh air is constantly supplied ~~to a space~~, thus helping to drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause ~~and treating it as such~~ which is the poorly performing fabric.	+	In such a scenario some arguments can be made in favour positive pressurisation to ensure fresh air is constantly supplied, thus helping drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause - which is the poorly performing fabric.

−	In 2020 the issue of poor indoor air quality (as a result of poor ventilation and fabric performance) lead to the tragic death of a young boy in Rochdale, UK. ~~In December 2020 a~~ coroner ruled that ~~a young~~ boy died from a respiratory condition which was caused by mould in a one-bedroom flat managed ~~organised~~ by a housing association~~, the~~ issue was ~~disscused~~ in Parliament and Michael Gove followed ~~up the incident~~ with various comments in November 2022. The Property Care Association (PCA) then called for more stringent enforcement of Building Regulations to tackle the problem of damp and mould in homes, of which its members said they were seeing a “significant rise” in.	+	In 2020 the issue of poor indoor air quality (as a result of poor ventilation and fabric performance) lead to the tragic death of a young boy in Rochdale, UK. The coroner ruled that the boy died from a respiratory condition which was caused by mould in a one-bedroom flat managed by a housing association. The issue was discussed in Parliament and Michael Gove followed with various comments in November 2022. The Property Care Association (PCA) then called for more stringent enforcement of the Building Regulations to tackle the problem of damp and mould in homes, of which its members said they were seeing a “significant rise”.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =

Designing Buildings at 07:05, 22 November 2022

2022-11-22T07:05:41Z

← Older revision		Revision as of 07:05, 22 November 2022
Line 1:		Line 1:
	[[File:Positive_Input_Vent_900.jpg\|link=File:Positive_Input_Vent_900.jpg]]		[[File:Positive_Input_Vent_900.jpg\|link=File:Positive_Input_Vent_900.jpg]]

−	~~Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and~~ is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure~~, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.~~	+	= What is positive pressure ventilation? =

−	~~= Simple solutions =~~	+	Positive pressure ventilation (PPV), also referred to as positive input ventilation (PIV), is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric. It has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.

−	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is ~~sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).~~	+	= How is positive pressure ventilation created? =

−	~~= Other solutions =~~	+	This servicing approach can be achieved by installing a single unit below a roof (see image above left) that draws in fresh, warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above). Alternatively, it can be achieved by a central fan integrated supply (CFIS), a central unit that pulls fresh air into a building which might be warmed by the space and supplied into the occupied areas (right hand diagram).

−	~~Such systems then~~ vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance~~, likewise~~ full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.	+	Systems vary in their degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance. Likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.

−	~~= Development =~~	+	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Also, in MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, teducing the amount of new heat energy required. In a PPV system the air effectively leaks out of the building fabric along with the heating energy invested in it, and the new fresh air needs to be preheated using a new energy source.

−	~~Positive Input Ventilation (PIV)~~ was ~~developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor~~ ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.	+	= When was positive pressure ventilation developed? =

−	~~It is important~~ to ~~note that although there are some similarities~~ to ~~MVHR~~, ~~the two systems are very different~~ in that ~~one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the~~ building envelope~~. Importantly also is that with an MVHR system the heat from stale warm moist air is retained~~ and ~~used to reheat incoming~~ fresh air~~, which means~~ the ~~heating energy already invested in that~~ air ~~gets recycled, this reducing the amount~~ of ~~new heat energy required, in a PPV or PV systems the air effectively leaks~~ out of the ~~building~~ fabric ~~along with the heating energy invested in it~~, ~~plus the new fresh~~ air ~~needs~~ to ~~be preheated using a new energy source~~.	+	Positive pressure ventilation was developed in the 1970's to deal with poor performance in existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea was that where a building envelope does not ventilate enough or has cold areas and moisture issues, pumping fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without more costly upgrades to the envelope.

	= Mould risk =		= Mould risk =

Editor at 09:46, 21 November 2022

2022-11-21T09:46:23Z

← Older revision		Revision as of 09:46, 21 November 2022
Line 2:		Line 2:

	Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.		Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.
		+
		+	= Simple solutions =

	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).		This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).
		+
		+	= Other solutions =

	Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.		Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.
		+
		+	= Development =

	Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.		Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.

	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.		It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.
		+
		+	= Mould risk =
		+
		+	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases heating, stale airwithin the building, cold spots in the fabric and drafts can cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as window or poorly insulated walls, growth of mould is likely to be worse in winter and worsened by poor ventilation and heating.
		+
		+	In such a scenario some arguments can be made in favour positive pressurisation balance to ensure fresh air is constantly supplied to a space, thus helping to drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause and treating it as such which is the poorly performing fabric.
		+
		+	In 2020 the issue of poor indoor air quality (as a result of poor ventilation and fabric performance) lead to the tragic death of a young boy in Rochdale, UK. In December 2020 a coroner ruled that a young boy died from a respiratory condition which was caused by mould in a one-bedroom flat managed organised by a housing association, the issue was disscused in Parliament and Michael Gove followed up the incident with various comments in November 2022. The Property Care Association (PCA) then called for more stringent enforcement of Building Regulations to tackle the problem of damp and mould in homes, of which its members said they were seeing a “significant rise” in.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =

Editor at 09:42, 21 November 2022

2022-11-21T09:42:09Z

← Older revision		Revision as of 09:42, 21 November 2022
Line 2:		Line 2:

	Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.		Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.
−
−	~~= Simpler solutions =~~

	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).		This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).
−
−	~~= Other solutions =~~

	Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.		Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.
−
−	~~= Development =~~

	Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.		Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.

	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.		It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.
−
−	~~= Mould issues =~~
−
−	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases heating, stale air within the building, cold spots in the fabric and drafts can cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as window or poorly insulated walls, growth of mould is likely to be worse in winter and worsened by poor ventilation and heating.
−
−	In such a scenario some arguments can be made in favour positive pressurisation balance to ensure fresh air is constantly supplied to a space, thus helping to drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause and treating it as such, which is the poorly performing fabric.
−
−	In 2020 the issue of poor indoor air quality (as a result of poor ventilation and fabric performance) lead to the tragic death of a young boy in Rochdale, UK. In December 2020 a coroner ruled that a young boy died from a respiratory condition which was caused by mould in a one-bedroom flat managed organised by a housing association, the issue was discussed in Parliament and Michael Gove followed up the incident in a statement in November 2022.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =

Editor at 09:40, 21 November 2022

2022-11-21T09:40:11Z

← Older revision		Revision as of 09:40, 21 November 2022
Line 3:		Line 3:
	Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.		Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.

−	= ~~Simple solution~~ =	+	= Simpler solutions =

	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).		This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).

−	= ~~More complex~~ =	+	= Other solutions =

	Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.		Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.

−	= ~~Background~~ =	+	= Development =

	Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.		Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.

Editor at 09:38, 21 November 2022

2022-11-21T09:38:28Z

← Older revision		Revision as of 09:38, 21 November 2022
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	* Effective ventilation in buildings.		* Effective ventilation in buildings.
	* Pressurisation of Closed Heating and Cooling Systems (BG 82/2022).		* Pressurisation of Closed Heating and Cooling Systems (BG 82/2022).
		+	* Pressurisation in buildings.

	[[Category:DCN_Definition]] [[Category:DCN_Product_Knowledge]] [[Category:Definitions]]		[[Category:DCN_Definition]] [[Category:DCN_Product_Knowledge]] [[Category:Definitions]]

Editor at 09:37, 21 November 2022

2022-11-21T09:37:54Z

← Older revision		Revision as of 09:37, 21 November 2022
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−	[[File:~~Positive Input Vent 900~~.jpg]]	+	[[File:Positive_Input_Vent_900.jpg\|link=File:Positive_Input_Vent_900.jpg]]

	Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.		Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.
		+
		+	= Simple solution =

	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).		This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).
		+
		+	= More complex =

	Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.		Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.
		+
		+	= Background =

	Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.		Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.

	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.		It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.
		+
		+	= Mould issues =
		+
		+	In a building that has low levels of insulation and air tightness as well as poor ventilation and in some cases heating, stale air within the building, cold spots in the fabric and drafts can cause higher levels of moisture and dampness which can lead to mould and air quality issues. Mould can form when excess moisture in the air comes into contact with cold surfaces, such as window or poorly insulated walls, growth of mould is likely to be worse in winter and worsened by poor ventilation and heating.
		+
		+	In such a scenario some arguments can be made in favour positive pressurisation balance to ensure fresh air is constantly supplied to a space, thus helping to drive moist air out through the poorly performing fabric. However as an approach this might be seen as a way of dealing with the symptoms of a poorly performing space rather than dealing with the root cause and treating it as such, which is the poorly performing fabric.
		+
		+	In 2020 the issue of poor indoor air quality (as a result of poor ventilation and fabric performance) lead to the tragic death of a young boy in Rochdale, UK. In December 2020 a coroner ruled that a young boy died from a respiratory condition which was caused by mould in a one-bedroom flat managed organised by a housing association, the issue was discussed in Parliament and Michael Gove followed up the incident in a statement in November 2022.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =

Editor at 11:40, 20 November 2022

2022-11-20T11:40:04Z

← Older revision		Revision as of 11:40, 20 November 2022
Line 1:		Line 1:
−	Positive pressure ventilation (PVV), also referred to as positive input ventilation (PIV) is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometime pre-warmed air) into a building, creating a positive pressure, which drives stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.	+	[[File:Positive Input Vent 900.jpg]]

−	~~This servicing approach can be achieved by installing~~ a ~~single unit below a roof~~ that ~~draws in the~~ fresh ~~but warmed internal~~ air ~~from the attic space and drives it into the occupied areas within the insulation line~~, ~~or through what is known~~ as ~~a central fan integrated~~ supply (~~CFIS~~) ~~where~~ a ~~central unit pulls fresh air which is than warmed~~, ~~into~~ the building~~. the installation of~~ a ~~more complex air handling unit~~ that ~~also contains a small extract element~~. ~~are a number of different ways to achieve this~~	+	Positive pressure ventilation (PPV), might also referred to as positive input ventilation (PIV) and is a ventilation system that focusses on supplying fresh air to a building, as opposed to full air conditioning with supply and extract. The system supplies fresh (sometimes pre-warmed air) into a building, creating a positive pressure, which can drive stale or moist air out through the building fabric, it has been considered as a remedy for issues such as condensation, damp or even mould that occur in some buildings.

−	[[Category:~~Articles_needing_more_work~~]]	+	This servicing approach can be achieved by installing a single unit below a roof ( see image above left) that draws in the fresh but warmed internal air from the attic space and drives it into the occupied areas within the insulation line (middle image above), or through what is sometimes known as a central fan integrated supply (CFIS) where a central unit pulls fresh air into a building which might be warmed by the space and supplied into the spaces (right hand diagram).
		+
		+	Such systems then vary in degree of complexity and function, potentially including intake ducts to help preheat the incoming fresh air, in a similar way to mechanical ventilation heat recovery (MVHR). However MVHR units tend to be fully balanced systems with the same number of extract ducts as supply ducts, aiming to achieve neither positive nor negative pressure but a balance, likewise full air conditioning with air handling units aim to balance supply and extract. MVHR systems rely on high level fabric performance in terms of heat loss and air tightness, this avoids the issues with drafts, cold spots and surfaces.
		+
		+	Positive Input Ventilation (PIV) was developed in the 1970's to deal with poor performance issues of existing buildings built to fabric performance standards considerably lower than today, in particular to tackle issues of poor ventilation and moisture build up. The idea is that where a building envelope does not ventilate enough or has cold areas and moisture issues, the pumping of fresh air into the space will over time dilute the stale air by forcing most of it out through the fabric, this maintains a better internal air quality without full more costly upgrades to the envelope.
		+
		+	It is important to note that although there are some similarities to MVHR, the two systems are very different in that one runs at constant positive pressure, whilst the other is in balance, relying on careful design and performance of the building envelope. Importantly also is that with an MVHR system the heat from stale warm moist air is retained and used to reheat incoming fresh air, which means the heating energy already invested in that air gets recycled, this reducing the amount of new heat energy required, in a PPV or PV systems the air effectively leaks out of the building fabric along with the heating energy invested in it, plus the new fresh air needs to be preheated using a new energy source.
		+
		+	= Related articles on Designing Buildings =
		+
		+	* Active pressurisation.
		+	* Air change rates.
		+	* Airflow
		+	* Airtightness of energy efficient buildings.
		+	* Design of isolation rooms for infection control.
		+	* Effective ventilation in buildings.
		+	* Pressurisation of Closed Heating and Cooling Systems (BG 82/2022).
		+
		+	[[Category:DCN_Definition]] [[Category:DCN_Product_Knowledge]] [[Category:Definitions]]