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Specification J5.2c Piping, Vessel, Heat Exchanger And Tank Insulation
1. Scope
(a)
This Specification contains the requirements for the insulating of piping, vessels, heat exchangers and tanks containing heating fluids or cooling fluids used in an air-conditioning system.
(b)
For the purposes of this Specification—
(i)
heating fluids include heated water, steam and condensate; and
(ii)
cooling fluids include refrigerant, chilled water, brines and glycol mixtures, but do not include condenser cooling water.
Intent
To clarify that provides the required performance of insulation on piping, vessels, heat exchangers and tanks containing heated or cooled fluids.
clarifies that provides the required performance of insulation on piping, vessels, heat exchangers and tanks containing heated or cooled fluids used in an air-conditioning system.
outlines that for the purposes of this Specification, heating fluids include heated water, steam and condensate and cooling fluids include refrigerant, chilled water, brines and glycol mixtures but does not include condenser cooling water.
Condenser cooling water is exempt from the minimum insulation requirements of this Specification due to the limited temperature difference between the piping contents and the surrounding space. This means there would likely be small energy savings achieved compared to the costs of insulation in these circumstances. However insulation may be installed for reasons other than energy efficiency such as for acoustics, or to minimise the risk of condensation forming.
2. Insulation
(a)
Piping, vessels, heat exchangers and tanks must be provided with insulation—
(i)
complying with AS/NZS 4859.1; and
(ii)
for heated or chilled water piping, having a material R-Value not less than that specified in Table 2a; and
(b)
Insulation must—
(i)
be protected against the effects of weather and sunlight; and
(ii)
be able to withstand the temperatures within the piping, vessel, heat exchanger or tank.
(c)
Insulation provided to piping, vessels, heat exchangers or tanks containing cooling fluid must be protected by a vapour barrier on the outside of the insulation.
(d)
The requirements of (a) and (b) do not apply to piping—
(i)
located within the only or last room served by the system; or
(ii)
encased within a concrete slab or panel which is part of a heating or cooling system; or
(iii)
supplied as an integral part of a piece of plant; or
(iv)
inside an air-handling unit, fan-coil unit or the like.
Table 2a WATER PIPING - MINIMUM MATERIAL R-VALUE
| Type of water piping | Minimum material R-Value |
|---|---|
| Heated water piping of all diameters | 1.5 |
| Chilled water piping with nominal diameters not more than 40 mm | 1.0 |
| Chilled water piping with nominal diameters more than 40 mm but not more than 80 mm | 1.5 |
| Chilled water piping with nominal diameters more than 80 mm | 2.0 |
|
Notes:
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Table 2b REFRIGERANT, STEAM AND CONDENSATE PIPING— MINIMUM MATERIAL R-VALUE
| Temperature range | Nominal pipe size | ||||
|---|---|---|---|---|---|
| 15 mm to 40 mm | 41 mm to 80 mm | 81 mm to 125 mm | 126 mm to 150 mm | 151 mm to 200 mm | |
| Refrigerant not more than 2°C | 1.3 | 1.7 | 2.0 | 2.0 | 2.7 |
| Refrigerant more than 2°C but not more than 20°C | 1.0 | 1.5 | 2.0 | 2.0 | 2.0 |
| Steam and condensate not more than 120°C | 1.0 | 1.0 | 1.3 | 1.3 | 1.3 |
| Steam more than 120°C | 1.5 | 1.5 | 1.5 | 1.8 | 2.1 |
Table 2c VESSELS, HEAT EXCHANGERS AND TANKS – MINIMUM MATERIAL R-VALUE
| Content of vessel, heat exchanger or tank | Minimum material R-Value |
|---|---|
| Refrigerant, brine or glycol that is not more than 2°C | 2.7 |
| Refrigerant or chilled water that is more than 2°C but not more than 20°C | 1.8 |
| Heated water | 1.4 |
| Steam | 2.5 |
Intent
To facilitate the efficient use of energy by detailing the requirements of insulating piping, vessels, heat exchangers and tanks containing heated or cooled fluids.
states that insulation must comply with the requirements of AS 4859.1 which covers materials for the thermal insulation of buildings - general criteria and technical provisions.
, and outline that insulation requirements are located in the following tables:
- heated and chilled water piping: ;
- refrigerant, steam and condensate piping: ; and
- vessels, heat exchangers and tanks: .
Note the R-Value is that of the insulation and not the Total R-Value of the pipe, air film and insulation. This approach is similar to ductwork insulation. Where piping has a significant inherent R-Value, it may be subtracted from the material R-Value required. However the inherent R-Value of most piping materials is not sufficient to satisfy the requirements in , and .
The insulation types in the following table are typical examples of materials that can be used to insulate piping and are provided for guidance only. The R-Values are calculated in accordance with AS/NZS 4859.1 as per the requirement in and averaged over a number of nominal pipe diameters.
| Insulation | R-Value |
|---|---|
| 13 mm of closed cell polymer | 0.6 |
| 19 mm of closed cell polymer | 0.9 |
| 25 mm of closed cell polymer | 1.3 |
| 25 mm of closed cell polymer | 1.3 |
The insulation values in are based on a nominal diameter of the water piping. The single required R-Value for each pipe diameter is intended to allow for straightforward installation on-site and compliance to be achieved.
outlines the extent of the insulation requirements and states that the piping to be insulated includes all flow and return piping, chilled water supply piping within 500 mm of the connection to the air-conditioning system and pressure relief piping within 500 mm of the connection to the air-conditioning system.
outlines scenarios where the required insulation R-Value may be halved. The concession in recognises the practical and physical limitations of installing thick insulation to small diameter piping where the pipework joins an item of plant. There is a further concession for valves in small bore pipes close to plant where there is insufficient space for installation, such as between a solenoid valve and the control motor. Similarly in , piping that penetrates a structural member is only required to have insulation installed that is half of the added R-Value required by .
is a concession for piping containing high temperature chilled water of more than 14°C as may occur in air-conditioning systems such as chilled beams. This exemption recognises that for situations where the contents of the pipework are similar to the surrounding ambient temperature, there are limited energy savings achieved by insulation.
specifies the insulation requirements for refrigerant, steam and condensate piping. Similar to the R-Values required are based on the nominal diameter of the piping. Note that whilst there are no minimum insulation R-Value requirements for piping less than 15 mm in diameter in , insulation may be installed for acoustic reasons or to reduce the risk of condensation forming.
specifies the minimum insulation requirements for vessels, heat exchangers and tanks with the values specified based on the fluid type and its likely temperature.
requires insulation to be protected from the effects of weather and sunlight, which may reduce its insulating properties. This protection may be achieved by ensuring that the insulation is enclosed in protective sheathing such as formed metal sheeting, external grade plastics or other similar material. Clause 2(b)(ii) requires insulation to be able to withstand the temperatures within the piping, vessel, heat exchanger or tank, otherwise degradation of the insulation's thermal performance may occur.
requires insulation to be protected by a vapour barrier if the piping, heat exchanger or tank contains a cooling fluid. This is to reduce the likelihood of condensation problems arising that are created by the internal temperature of the piping, heat exchanger or tank being below the dew point of the external air.
outlines piping that is exempted from meeting the requirements of and , where;
- piping is located within the last space being heated or cooled as the heating or cooling effect is intended for that space anyway, or
- in a slab or panel that is specifically designed as a heating or cooling system, such as an in-slab or in-screed heating or cooling system. This is because the insulation would contradict the aim of the heating or cooling from the piping. However, this exemption is not intended to apply to distribution pipework.
and exempt piping that is supplied as part of an item of plant such as a chiller or boiler or inside an item of plant such as an air-handling unit, fan-coil unit or the like.
Insulation requirements for piping containing heated and chilled fluids is explained in the following example.
Example
Example
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Figure Spec J5.2c(1) APPLICATION OF WATER PIPING INSULATION |
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The piping insulation requirements would be as follows:
- For heated water piping, insulation with a material R-Value of 1.5 would be required to be installed. However for the heated water piping section that passes through a structural wall, a concession is available as described in Table 2(a) - Note 2(b). This results in a minimum required insulation R-Value of 0.75 for the section of supply and return piping.
- The chilled water supply and return piping has a 60 mm nominal diameter. This means an added R-Value of 1.5 is required to be installed on this piping as per Table 2a.