Advantage 1: High air-tightness
As known to everybody,no matter whether to send gas or send materials by gas,leakage shall be mostly avoided.Then,how can
the airpipe succeed in this? It is because the accessorial parts of the round airpipe and every other part to be connected with
the pipeline bear an airtight joint fitted by the factory.During the installation just insert it into the round pipe only and
a very high airtightness can be achieved.Exactly according to the international CEN pipeline airthightness standard with such
a joint arrangement a Grade C anti-leakage performance can be reached. The airtight joint is composed of double rubber
hermetic sealing rings (See the figure) When the joint connects with the piping part,the sealing ring is compressed,capable of
affording a pressure of +30000Pa and -5000Pa,therefore,a necessary airtightness can be ensured.The round straight pipe at the spiral
holder never gives a leakage.With the application of the airtight joint the air-leakage rate of the entire air pipe system
will drop down to minimum.The leakage with the airpipeline is due to the connection of the piping parts in a great deal.
Compared to the rectangular pipeline.a typical round pipe is 3-6m long,while the former is 1-1.5m only. The sealing washer
for the rectangular air-pipe is manually made,undergoes a rough installation and it is impossible to install such washer by
the factory like the round pipe sealing ring.Moreover the sealing area of the round piping has a shorter circumference,while
under the identical sectional size the 1:3 width-length proportioned rectanglular piping has a circumference 41% longer than
that of the round piping.So with the round piping the air-leakage area has reduced a lot.
　　　　　　　

Advantage 2: Low installation cost
Under the equal resistance ,in the same installation space a 250x250mm rectangular pipeline can be replaced by a Ф200mm
round one resulting in a 50% less cost of installation than that for the former.Replacement of one piece of rectangular
piping with two or several pieces of round pipings can reduce the cost, too.The following figure shows a contrast of round
piping with rectangular piping in the installation cost based on an almost identical sectional size but in different
corresponding conditions of diameter(round piping) and length-width proportion(rectangular piping).

The following figures give some selective schemes to replace the rectangular piping with the round piping system. The
flow for calculation for all the systems is 0.5m3/S.
The flow speed and the resistance are as shown in the figure. The installation cost in the right (including transport,
packing and loss) relates to the rectangular air piping.
Then,why can the installation cost be cut down by using the round piping?
1.High degree of serialization and standardization;
2.High automatized and systematized production of pipings and joints.
3.The round piping system can be installed by one person only,while at least two persons are necessary to operate with
the rectangular piping system.The round pipes can be made in a 6-metre length or more,and just to complete the job by
one insertion move only,while a piece of 6m-long rectangular pipe at least shall be divided into 3-4 parts which are
to be connected with flanges.This increases not only the links of leakage but also time consumption for installation.
4.For such pipelines that require a protection on their outer walls for heat preservation,against rain and corrosion,etc.
the round piping can be easily fitted with protectives thanks to its property.Compared to the rectangular piping the round
piping has a shorter circumference,so requires the protective materials 13% less ,taking a Ф500mm round pipe and a
500x400mm rectangular pipe for example.
5.Thanks to its top strength the round piping allows to reduce both the number and dimension of the hanging frame and
supporter for installation.This can not only reduce the expense for the hanging frame and supporter-making,but also cuts
down the time consumption on installation by 20%.
6.Equipment for the round pipe moulding may be placed on the spot for operation,which brings a reduction of the piping
transport charge and avoids the transport damage.
7.As known to everybody, under the equal sectional size,the round piping features a minimum material consumption.The
round airpipe to be moulded at the spiral holder allows to reduce the thickness of the material accordingly thanks to its
high strength.
1.High degree of serialization and standardization;
2.High automatized and systematized production of pipings and joints.
3.The round piping system can be installed by one person only,while at least two persons are necessary to operate with the
rectangular piping system.The round pipes can be made in a 6-metre length or more,and just to complete the job by one
insertion move only,while a piece of 6m-long rectangular pipe at least shall be divided into 3-4 parts which are to be
connected with flanges.This increases not only the links of leakage but also time consumption for installation.
4.For such pipelines that require a protection on their outer walls for heat preservation,against rain and corrosion,etc.
the round piping can be easily fitted with protectives thanks to its property.Compared to the rectangular piping the round
piping has a shorter circumference,so requires the protective materials 13% less ,taking a Ф500mm round pipe and a
500x400mm rectangular pipe for example.
5.Thanks to its top strength the round piping allows to reduce both the number and dimension of the hanging frame and
supporter for installation.This can not only reduce the expense for the hanging frame and supporter-making,but also cuts
down the time consumption on installation by 20%.
6.Equipment for the round pipe moulding may be placed on the spot for operation,which brings a reduction of the piping
transport charge and avoids the transport damage.
7.As known to everybody, under the equal sectional size,the round piping features a minimum material consumption.The
round airpipe to be moulded at the spiral holder allows to reduce the thickness of the material accordingly thanks to its
high strength.

Advantage 3: High standardization of the products
Every component of the round piping system is standardized,facilitating the storage and shortening the transport time.
Thanks to the size standardization,the complete serial piping pieces and joints may be manufactured and stored in advance,
while the diameter of the round pipe is to be settled according to the CEN Standard. The following table shows the
arrangement of diameters according to a geometric priority step number system:


Once the engineering drawing has been determined the high speed automatic pipe-making machine will make out the air pipes
in different diameters and lengths immediately,which may be carried to the operation spot together with diverse piping
accessories and joints,taken from the warehouse for installation.
In the process of installation,in case of the drawing modification for the round piping system it is very easy to follow
the modification quickly just like to handle a trifling matter,furthermore,very easy to re-cut the piping pieces precisely
to the modified sizes of installation on the operation spot.
As for the rectangular air piping system it will be very difficult to carry out an on-the spot modification and adjustment
because all the piping materials of this kind are almost made to orders.

Advantage 4: Small space of installation, elegant and in-good taste arrangement
Thanks to the special way of connection applied for the round piping system,the flange-based connection is cancelled,
resulting in a less space occupation than the air-piping connected with flanges.Furthermore,thanks to no more existence of
the rings and rings of flange edges,there is not only little air leakage,more effective warmth preservation,but also looks
more beautiful to eyes.Especially,if an exposed installation scheme is wanted for the piping system,the round piping
system will be the best choice.
Advantage 5: Easy measurement
Any aerodynamic property measurement and wind-tunnel test are based on the round air-pipings.So applying a round piping
system in the engineering actions allows to achieve the most easiness and top precise result of measurement in the
aero-property testing. It is even possible to install fixed measurement devices on the engineering spots for the purpose
to carry out daily routine tests and effect the remote control.

Advantage 6: Top strength and less consumption of material
The round air piping with the spiral holder is much more stronger than any other formed air piping . Figure 1 shows the
data of pressures exerted on the different-caliber air pipings without causing any deformation.Figure 2 shows the data
of pressures without causing any damage.
From this people can draw a conclusion that thanks to the excellent structural feature the round piping with the spiral
holder allows to use materials of more thinner thickness,resulting in less weight and dimension than the rectangular
piping system under the identical conditions. This will lessen the weight load on the architectural buildings a lot. For
a typical piping system composed of the straight pipes,elbows and diameter-varying joints,the rectangular piping weighs
30-40% heavier than the round piping.Light weight means an easy installation.What’s more,reduces the material
consumption.So the round piping system is really an excellent solution to cut down the cost to a great extent.

Advantage 7: Less loss for the pressure dropping
As a common knowledge for everybody,under an identical volume,the round piping generates a much smaller resistance than
the rectangular one.Logically, with the round piping system there will be much less loss at the pressure dropping than
the rectangular one.Therefore,when select electric fans they require the supporting motors with a smaller HP,therefore,
greatly cutting down the daily running cost of the system and lessening the initial investment on the fans.

Advantage 8: Easy cleaning of the piping inside cavity
Dusts and mould collected both in the air-sending and return channels continuously spread into the surrounding buildings
creating a big problem of the “morbid” buildings.The International Building Health Congresses repeatedly
emphasized the necessity to clean the air channels which have brought the buildings to the morbid state. Thanks to its
normative diameters and advantageous geometric form,compared to the rectanglular piping it is much easier and financially
cheaper to clean the round piping: may apply either dry,or wet cleaning method,may very easily do cleaning with a
spinning brush connected with a vaccum cleaner,leaving absolutely no dead angle