- INTRODUCTION
Frontier Plumbing & Heating Supply is a specialty
supplier of Hydronic Floor Heat systems and all the accessories, complete with
experts with many years experience on staff. Our staff has been involved in
projects as small as a bathroom floor or heated towel rack too as large of
projects as high-rise office towers. We can do industrial design to residential
homes or anything in-between.
Our services are very extensive and cover all
your heating needs. We also keep in inventory a large and complete selection of
major components for your convenience. We can service any project no matter the
budget range or the size of job.
Some of the services provided:
- complete packages
- pre-plumbed pumping and control panels
- system design
- project design build
- freezer sub soil heat
- indoor pool dehumidification
- make up air system
- slab heat systems
- wood floor staple up heat system
Back to Technical Information Page
- RADIANT SURFACE HEATING
Radiant surface heating is an efficient, cleaner,
more comfortable, and healthier method of heat distribution which effectively
reduces overall fuel consumption in both residential and commercial buildings.
Floor heating can save as much as 10% to better than 50% on the fuel bill.
Back to Technical Information Page
- HOW DOES IT WORK?
Radiant heat relies on the heating of entire
surfaces of space which, in turn, radiate an even, comfortable warmth to the
objects, occupants and surfaces of a room without first heating the air. Where
conventional heating systems rely on high temperatures delivered to a few low
surface area convectors, first warming the air and depending on convection to
transfer the warmth for the air to the occupants, radiant surface heating
provides lower level warmth to entire surfaces which in turn radiate heat
directly to occupants and objects within the space. Surfaces stay warm, floor to
ceiling temperatures remain more nearly constant, relative humidity remains
higher, and room air feels fresher.
Back to Technical Information Page
- WHERE CAN IT BE USED
Radiant surface heating is most commonly installed
in floors; either within slabs, or within or under wood floors. It can also be
installed within walls or ceilings.
Back to Technical Information Page
- WHAT ARE THE ADVANTAGES
Full, even, surface warmth rather than isolated
heating units. Heat distribution from floor to ceiling closely approaches
"ideal" heat distribution. (In conventional heating, heat is stratified,
concentrated in the upper third of the space height). Body warmth is retained.
Heat radiates directly to occupants. Radiant heat does not create drafts,
typical of conventional heating system.
As drafts are less of a problem so is dust.
Radiant heating does not transport dust particles, making it the choice where
allergies or spread of infection are considerations. Operates at lower
temperatures. Where conventional heating systems rely on high temperatures
delivered to relatively small surface areas, radiant surface heat utilizes lower
levels of heat over large areas. This allows boilers to operate more efficiently
and with reduced fuel consumption. Lower fuel bills. While fuel efficiency and
cost is specific to the installation, studies have shown radiant surface heating
yielding equivalent comfort levels at substantial fuel savings. Ideal for
larger, open areas with high ceilings. Because of a lower rate of convection and
stratification, radiant floor heat is particularly beneficial in large open
areas where heat loss to unused areas within the space create a problem for
conventional heating. No restrictions on furniture placement caused by obtrusive
convectors. As radiant floor heating is installed either under or within space
surfaces, usable square footage is increased and furniture placement is not
hampered by units within the room.
Back to Technical Information Page
- PERFORMANCE OF SYSTEM
A radiant system will only work if some careful
planning is done prior to the installation. We also know that it is very hard to
change a system once it is installed, we would ask then that if additional
information is needed other than contained in this manual the reader would
contact Frontier Plumbing & Heating Supply LTD.
Back to Technical Information Page
- FLOOR THERMAL CONDUCTIVITY
We must take in to account the amount of heat that
the floor has the ability to conduct. The floor must be able to transmit enough
heat to meet design heat loss condition. The less thermally conductive floors,
such as thick carpets, particularly with insulating pads, may require relatively
hotter water.
In general the more thermally conductive floor
coverings, such as tile, concrete toppings, brick, and thinner vinyl flooring
will respond faster to temperature change than carpeted floors. In residential
most floor coverings will work if the system is designed properly.
Back to Technical Information Page
- DESIGN CONSIDERATIONS
There are a number of things common to the design
of radiant floor heat system regardless of whether the installation is to be in
a concrete slab, wood floor, wall or ceiling.
Back to Technical Information Page
- RADIANT POTENTIAL
The amount of energy a radiant floor heat system
can deliver increases with the temperature difference between the radiant
surface and the heated space. This amount, in B.T.U. per hour per square foot,
has been found to be twice this difference.
For example, if the minimum desired temperature
of the heated space is 70 degrees F and the radiant surface temperature is 85
degrees F, 30 B.T.U./hr/sq.ft. can be delivered. (2 x delta T = 2 x 15 degrees F
= 30 B.T.U./hr./sq.ft.)
PLEASE NOTE: To assure occupant comfort in
residential and commercial applications it is suggested that radiant floor
surface temperatures not to exceed 85 degrees F. For other occupancies such as
light manufacturing, factory or warehouse buildings, higher heat loads may
require higher surface temperatures.
Back to Technical Information Page
- LIMITATIONS
There are a few situations in which a floor heating
system may not be able to deliver enough heat. One example of this would be a
greenhouse addition, with high glass walls, sunken floors, and a carpeted floor.
In cases like this, or in other examples where design heat loss may exceed 36
BTU/SQ/FT/HR, the prudent contractor may have to install auxiliary heat delivery
sources. Good choices include baseboard heat, fan coils, radiant wall or ceiling
panels, a wood stove or other.
Back to Technical Information Page
- STEADY HEATING REQUIREMENTS
A floor heat system, due to its nature, requires a
longer period of time to respond to changes in its thermostat setting. However,
once the thermal mass of the floor is heated, it is usually easy to maintain the
desired level of comfort. This means appropriate use of floor heating is where
the structure is kept a constant temperature.
Because of the slower response time of radiant
floor heat systems, a careful study of each project should be made. Special
consideration should be given to situations such as churches and conference
rooms, where sudden change in occupancy levels may cause significant changes in
the internal heat gain. This sudden heat gain along with the heat output of the
floor, may cause an unwanted rise in the temperature of the room. This is
particularly true in rooms with relatively low ceilings. System controls that
anticipate these internal heat gains may be required.
Back to Technical Information Page
- HEATING SYSTEM CONTROL
Zoning
Zones are areas of independently control
temperatures. Wherever individual temperature control of an area is desired, a
zone is defined. For example, a living room may be differentiated from a
bedroom, a kitchen, a bathroom, a garage area, etc. Zones are physically defined
by providing an individual piping circuit controlled by a pump, a zone valve, or
a mixing valve depending on the circumstances. A thermostat with a sensing
element located within the zone controls the pump or control valve, thus
regulating the temperature in that area.
Zones with floor surfacing that conduct heat
well may require tempering to avoid overly warm floor surfaces. A surface
temperature of 85 degrees F or under is generally recommended based on comfort.
Differing floor coverings conduct heat differently. However, the supply
temperature necessary to attain a design surface temperature in a heavily
carpeted room may prove too effective in areas with more highly conductive
surfaces. Areas such as these that require significantly less heat input may be
separately zoned and differentiated by a tempering (mixing) valve.
Valves and pumps can be thermostatically
controlled or totally manual, whatever the choice. Whichever the choice it is
important that access to control systems and headers be available.
Back to Technical Information Page
- ZONE DETERMINANTS; WHERE TO CREATE ZONES
Surface Conductivity:
Floor coverings with highly conductive surfaces
which require significantly lower fluid temperatures to reach design floor
surface temperatures than adjacent floor areas should have a zone separation.
For the purpose of design, a difference in R value of one can be considered as
significant. This difference will typically indicate a required heat fluid
temperature difference in the area of 20 degrees F.
In situations that a fluid would need to be 20
degrees different in one area to the next would indicate the need for water
tempering equipment or a zone valve to shut off the area with the floor covering
with the lesser R value. Zoning is very important in floor heating, it is the
only way to prevent uneven heating in a building.
Preference or Usage:
Zone size, convenience, space use, degree of
independence or specialty uses desired, are among the many reasons for creating
additional zones.
Each room, and in fact, discrete portions within
rooms can be inexpensively independently zoned and controlled.
Heat load:
Areas of dissimilar heat losses of more than 5
degrees F should be separated into areas of their own zone. This again is the
only sure way of controlling or balancing the heat. Mixing valves or balancing
valves can be used but requires more manual input than simply adjusting a
thermostat. Now that the zoning areas are determined then the proper amount of
heat must be provided to each area to ensure that adequate heat is available on
the cold days and not overheat the milder days.
Back to Technical Information Page
- LOOP LENGTHS AND SPACING
In general, loop lengths from a single header and
multiple headers within the same zone should be equal in length to ensure equal
flow in each loop and should be laid out in a uniform pattern of consistent
spacing to ensure even heat distribution. The actual length of the loop is
determined by the area the heat is to be provided to and by the limitations that
the size of tubing will adequately handle. Each tubing we distribute has a
different inside diameter, therefore they all have a different maximum length
that can be used. This length is to be determined by a qualified designer that
can calculate the pressure drop in the selected tubing. Radiant Design and
Supply will help determine this length for each project based on the pressure
drop information the tubing manufacture has provided us.
Although alternative spacing are acceptable, 5
to 16 inch spacing between tubing loops are typical choices depending on the
application and the heat load. A typical installation will have a closer spacing
in the areas of heat losses, such as the exterior walls, windows, and doors of a
building. This meaning that the tubing will be more concentrated around the
perimeter of the building and become a little further apart as the center of the
building is done. The only thing when doing this is to make sure that as many
tubes as possible make contact with the exterior of the building, this is to
even out the temperature drop in each loop of tube. The actual spacing required
in any project should be determined by a qualified person in the floor heat
industry and familiar with the flow capacities of the selected product. Frontier
Plumbing & Heating Supply Ltd. will assist in the calculation of the proper
spacing of the appropriate tubing for the job to be done.
Back to Technical Information Page
- FLOW RATES
The flow rates of a job are determined by the heat
loss of the given area, with out a proper heat loss then the flow rates cannot
be correctly figured, therefore the spacing cannot be accurate. The G.P.M. of
the system is determined by dividing the total B.T.U.s of the zone by the design
or suggested temperature drop, then divided that by 60 minutes in an hour then
that is divided by the specific heat of the heat transfer fluid. The GPM figure
is then divided by the suggested tubing flow rate to determine how many runs
will be required to provide the proper energy.
Back to Technical Information Page
- PRESSURE DROP
Most hydronic heating systems are closed loop
systems. The same water is pumped around over and over again. That being the
case pumps only have to be overcome the friction of the fluid resistance through
the system. The amount of force to push the fluid through out the tubing system
depends on the viscosity of the fluid, the amount of water each individual tube
will carry, and the total distance the fluid has to travel. You may use the
following calculation to determine the pressure drop through a length of floor
heat hose, as long as the loop length is known and the GPM per tube is known.
P=?*x(v) 1.6xL
- Where:
- P= pressure drop in feet of head
?*= changing multiplier based on the tubing
(provided by manufacturer)
v= flow rate per individual tube
L= length of a loop of the selected tubing
()= this number is raised to the power of 1.6
Back to Technical Information Page
- PUMP SIZING
Once the flow rate of the pump circuit and the
pressure drop for the zone or the pumping area is determined, a pump curve table
can be used to select the proper pump. Be sure to calculate the total pressure
drop by adding up all the drops due to the piping, valves, elbows, and the
boiler or heat source.
Back to Technical Information Page
- HEADER and PIPE SIZING
For the majority of the residential and commercial
radiant heating systems with flow rates less than 15 gpm, a standard l inch
diameter copper header is used. Larger diameter headers are available for flow
rates greater than 15 gpm. To determine the supply and return pipe sizes
required, use the following pipe sizing guide:
Back to Technical Information Page
- TABLE 1
| FLOW RATE |
PIPE SIZE |
| 3 to 7gpm |
.75 inch |
| 7 to 15 gpm |
1.00 inch |
| 15 to 30 gpm |
1.50 inch |
| 25 to 50 gpm |
2.00 inch |
Back to Technical Information Page
- REVERSE RETURN PIPING
Multiply loop distribution and return headers
should be piped in for reverse return to avoid short circuiting and to ensure
balanced flow by creating an equal pressure drop across each fluid path in the
zone.
Back to Technical Information Page
- TEMPERATURE CONTROL
Control system options are many but typically
include tempering (mixing) valves to control the temperature of the heat
transfer fluid in the system and the zone valves to control entry of heat
transfer fluid into individual zones. The most desirable method of fluid
temperature control for a radiant floor heat system is one which responds
immediately to changes in outdoor ambient temperature. This is known as "indoor
outdoor reset". A control unit senses changes in outdoor temperature, and
adjusts the boiler temperature, or the position of a tempering or mixing valve
to regulate the temperature of the water supplied to the system.
Back to Technical Information Page
- HEAT TRANSFER FLUID TEMPERATURES
The heat transfer fluid temperature in a hydronic
radiant floor heat system is generally lower than that of baseboard, radiator or
coil heating system. For example, a baseboard system is most often sized for
water at 180 degrees F. Floor heating systems, on the other hand, rarely require
temperatures above 150 degrees F with typical operating temperatures of 100 deg
to 140 deg F. This is because the heat transfer area (Floors) is very large
compared to that of other types of systems. The average fluid temperature
required are dependent upon the thermal resistance values of the materials
between the heat tubing and the radiant surface, and the desired temperature of
the heated space. Heavily carpeted floors, for example, will require higher
fluid temperatures than bare floors.
Back to Technical Information Page
- DESIGN TEMPERATURES
Once preliminary design is complete, heat transfer
fluid temperature requirements of the zones can be approximated. The boiler will
be expected to supply the highest heat required by any zone plus any contingency
output desired, usually at least 10%, at the design flow rate. Tempering valves
are used to de-rate areas which this highest heat requirements would prove
uncomfortable warm.
An alternative, and necessary adjunct to
calculating and setting design fluid temperature requirements is experience in
use. Assuming zoning has properly taken into account significantly divergent BTU
delivery requirements, tuning of BTUs delivered and resulting surface
temperatures reached are easily accomplished through adjustment of tempering in
operation.
To calculate required average heat transfer
fluid temperatures for the design conditions, the total R value of the materials
between the floor heat tubing and the room is multiplied by the design heat load
per square foot. This figure is added to the desired temperature of the heated
space. The design heat load is the rate at which energy is lost by the structure
at the winter design conditions for the geographical area. Design fluid
temperature = minimum desired temperature of heated space + (design heat load
per square foot in BTU X sum of R values). Example = 70 degrees F. + (25 BTU/sq.
ft.x 2.62R) fluid temperature = 135.5 degrees F.
Back to Technical Information Page
- DESIGN AND LAYOUT
The first thing that must be done is the location
of the header is to be determined, the low profile of the headers allows easy
concealment within even a 2x4 stud wall. When considering header placement, a
number of tradeoffs need be considered. Among these are convenience of location,
accessibility, distance to supply source, tube layout and run preference, and so
on. Each of these considerations is arbitrary, but each will play a role in the
final placement decision, which, in a large zone, includes whether multiple
header locations is preferable to ganged headers.
Next is to determine the total length of
materials required for the project, this is determined from the spacing of the
tube plus the square footage of the zone. Refer to Radiant Design Supply for
more help in this area. To determine the loop lengths within the given zone by
analyzing the maximum distance the tube will have to travel based on the
location of the header, this will become the run length for that zone. The
pattern that the tubing takes to canvass the area to be heated plays no
significant roll only the spacing between the runs of tubing. In most cases this
will be relatively straight forward. In others however, there may be obstacles
for direct access to some sections of the zone and the path may require ganging
loops through a narrow opening, such as a doorway, before spreading into the
specified spacing. You will find that the first runs to lay down around the
outside of the structure will be straight and easy to place, the loop runs in
the center of the area will be different in there layout because they have a
lesser distance to travel, these last runs will run back and forth maintaining
the proper spacing using up the required length of tubing.
Back to Technical Information Page
- INSTALLATION REQUIREMENTS
The total number of runs that will be required can
be determined on the job site by cutting the runs off the roll as you go, so not
to cut too many runs and just judge how many to use by determining the length of
the runs. Then keeping the runs all equal length fill in the spaces to be heated
with tubing at the designed spacing. The other method is to have the design heat
load converted to gpm and then the number of loops can be calculated to the
number of loops required as shown previously. The number of loops required to
heat an area can also be determined by a detailed design provided by Frontier
Plumbing & Heating Supply LTD.
In Slab Installations:
The slab should be prepared using good
construction practice, this will result in a good radiant installation. It is
recommended that all floors to be heated be insulated on the exterior, and that
all slabs have vapour barrier installed to stop moisture from entering the
building. It is also recommended that insulation be installed throughout the
slab to help the heat system to respond to rapid heat changes. The location of
the header will have to be determined, some good choices are in the boiler room,
a closet, or suspended under the joist. The location of the header should also
allow for the tubing to be able to reach all areas of the floor to be heated but
also try and keep runs as short as possible. The header in concrete
installations should never be cast into the slab, the copper manifold should
remain out of the slab to stop damage from any movement the slab may undergo.
The tubing materials that should be used for floor heating should always be able
to take the normal movement of the slab in the event of cracking. The specified
tubing can be installed either over or underneath the reinforcing steel or mesh.
Placing the tubing down before the mesh will help hold the tube in place.
However, placing the tubing on top of reinforcing lets you tie the tubing to the
mesh or steel. The main thing to consider is that the spacing asked for is
maintained and that the tubing is kept for moving around. Floor heat tubing
loops should be placed from the outside toward the center. This makes sure that
adequate tubing is placed around the exterior of the floor area, to ensure the
heat loss to the outside is met. This makes sense because this is where the heat
loss is.
Under Wood Floor
Installations:
For installations under a joist supported floor
tubing of designed spacing is installed between the joist by stapling the tube
to the under side of the sub floor. This stapling is done by special staplers
for this purpose. The tubing should be supported with a staple every 8 inches,
to stop any sagging that may occur with the weight of the warm water. The tubing
is run from one end of the zone area to be heated, from a header system of
supply and return at the edge of the zone, these headers can be under the floor
joist or be placed in a closet or other accessible area. Once the tubing has
been installed to spacing required for the project then a foil faced insulation
must be placed in the joist space below the tubing, leaving space to make sure
the foil does not touch the heat tubing.
Above Floor Installations:
A number of methods are used to install Radiant
floor heat tubing on top of existing flooring. The two most common are:
- installation in a layer of light weight gypsum
concrete,
- installation between sleepers.
Light weight gypsum based concrete normally
1.25" to 1.5" in thickness is used to cover the floor heat tubing. This method
can be used in all types of installations and is the popular retrofit solution.
This method of installation, either on a sub floor in a new construction of over
an existing floor, consists of:
- covering the floor with water proof sealer to
ensure that there is no warping during the concrete pour,
- fastening the tubing to the floor on 8" centers
using staples,
- pressure testing the tubing and maintaining the
pressure during the pour.
Another above floor installation method involves
placing the radiant floor tubing at the specified spacing, between sleepers
which support the finished flooring. In addition to new construction, this
method is particularly suited to rehab and renovation work. Sleepers are
installed on the sub-floor with a gap sufficient to accept the floor heat tubing
and the tubing is laid in the space created. Alternatively, the tubing is placed
down first, then the sleepers are placed between the loops of tubing. Needless
to say, when securing the finish floor, care must be taken that no fasteners
penetrate the floor heat tubing.
Back to Technical Information Page
