12. DENIS FORMULA – REVISION
#4 – METRIC
12.2 STANDARD METHOD OF MEASUREMENT
FOR INSTALLED INDUSTRIAL INSULATION
These standards are to be used for the express
purpose of measuring the quantities of insulation required for
a mechanical system. They can be used for tendering, evaluation
of bids, and for finalizing accounts.
1. Insulation of mechanical systems including,
but not limited to, vessels, equipment, exchangers, pumps, tanks,
ducts or flues and pipe work.
2. All measurements shall be taken on the external
surface of the insulation system.
3. There shall be no deductions for surfaces
not insulated within the specified insulation area. Exceptions
to this rule may be negotiated where termination of insulation
does not require a finish or weatherproofing and/or where the
uninsulated portion is more than 5% of the total.
4. Irregular shapes, fittings on piping systems,
valves, etc., shall be counted separately. The conversion tables
of the formula are designed to include for general requirements.
Conversion factors for unusual items, e.g. seismological anchor
or hangers, shall be negotiated by the parties prior to commencing
5. All obstructions and penetrations of the
insulation system shall be measured separately.
6. All effected areas and pipe lengths shall
be multiplied by the complete applicable unit prices.
Types of insulation: hot, anti-condensation, cryogenic,
General description of items to be insulated:
Towers, columns, drums, containers, receivers,
exchangers, storage tanks, etc.
Equipment which has an irregular outer surface,
e.g. transitions, stiffeners, heads, roof ends, turbines, pumps,
compressors, air or gas handling fans, etc.
(c) Flat Surfaces
Boiler walls, precipitators, hoppers, ducts & flues,
storage bins, etc.
Straight pipes, bends, elbows, accessories,
fittings, valves, flanges, strainers, termination points, bevels,
Measuring and controlling devices for process
(f) Height allowances
Standards, see page DF-6.
PRINCIPALS OF MEASURING EQUIPMENT
Shell – Cylindrical
The outside diameter of the vessel plus two times
the insulation thickness multiplied by 3.14 and by the length,
tangent line to tangent line, as illustrated in diagram. Transition
sections (changes in diameter) shall be measured using the larger
diameter, times the length. There shall be no deductions for manholes
and any other interruption or projection, whether insulated or
Any irregular shape shall be measured on the outside
of the insulation surface, using the largest diameter. The surface
area for irregular surfaces to be multiplied by a correction factor
of 1.75 to obtain the equivalent area of flat surface. For small
pumps, turbines, etc. the minimum equivalent area of measurement
shall be 1 sq. meter.
Heads, Roofs, Ends
Flat: The surface area with diameter outside of
the vessel insulation.
Spherical: The surface area of the hemisphere
with diameter outside of the vessel insulation.
Dished: The surface area of a flat circle with
a diameter outside of the vessel insulation, multiplied by a correction
factor of 1.37.
Cones: The geometrical surface area of the cone,
measured outside the insulation thickness.
On "Unit Price" contracts, all insulated
nozzles and man-ways connecting to a vessel will be measured as
pipe run to the vessel wall plus flange. In addition, all nozzles,
man-ways, brackets, platform supports, obstructions, and penetrations,
shall have their perimeter measured as irregular surface. All penetrations
shall be a minimum 0.1 sq. meter per each.
On "Lump Sum" contracts, where like
obstructions, penetrations, nozzles, brackets, supports, stiffener
rings, etc. have not been shown in detail on bid drawings, they
shall be measured, as above, as extra work to the contract.
PRINCIPALS OF MEASURING
Pipe shall be measured from center line to center
line through all fittings, in accordance with Diagram 'A', Page
10. All fittings will be counted and classified for multiplication
by the appropriate factor listed in the "Fitting Factor Tables" Pages
5 to 8. Fittings connecting two or more different sizes of pipe
shall be counted as the largest size involved.
Shall be measured on the outside radius of the
Insulation sized to accommodate tracer(s) shall
be measured at the actual size of insulation used.
Tracer loops shall be measured separately.