Internal Floating Roof (IFR)

Brick Style Honeycomb Type with Full Contact


Third-Party Certification


IFR Honeycomb Floating Panel

  • Hi-tech aerospace technology is used to design the honeycomb floating panels with high-strength, making it a highly reliable product.
  • Third party SGS test result: it can stand up to 1267kgf

     (Sample size: 200x200mm, hydraulic machine is used to apply uniform pressure.)

  • Discountinous honeycomb floating panel, light weight and high buoyancy:                      API 650 gravity standard 0.7 / floating panel gravity (panel weight 12500g / panel volume (5x58x290)cm3)
  • This calculation is based on standard panel buoyancy and reaches 4.7 times its dead weight.
  • The liquid will not infiltrate the honeycomb core because the 4 corners of the floating panel are fully welded. Gas leaking test is used in all 4 corners to ensure 100% sealing. Afterwards, the panels are marked with coding numbers, and delivered to the customers.


IFR Support Leg

  • The support legs work independently from the floating roof and will not damage the whole structure.
  • Third party SGS stress test result for support leg's structure shows that it can support 2988kgf.
  • The support leg, support leg well and support leg pad can automatically adjust by themselves when resting on the tank bottom.
  • The upper part of the support legs have socks to prevent the VOC emissions. The socks materials depend of the stored liquid.


IFR Structure

  • The floating roof and the support legs are joint by beams to form one continuous strong structure. This structure is tested by SGS, and can support 1200kgf (more than 12 persons can safely walk anywhere on the roof).
  • 3rd party SGS oscillation test: the test frequency range: from 60-110 times/min and lasted for 1h. There were 5100 shakings. When the test was completed no deformations occured.

VOC Field Measurement Reports - Case Studies


VOCs Calculations

Formula's Source:

EPA-AP 42 Chapter 7


Calculation Parameters:

★Diameter: 20 m              ★Stored liquid: naphtha

★Temperature difference (est.): avg. high 15 ℃ , avg. low 3℃

★Capacity: 5000 m³         ★Cycle: every 7 days

★Avg. daily solar radiation energy: 1135btu/ft²  day.


With No IFR
Calculation types:

1. standing storage loss

2. working loss

Based on the calculation formula, the annual vapor loss is around 205.3 t/yr


With Skin & Pontoon Type IFR
There is no calculation formula for Skin&Pontoon IFR type under EPA-AP 42
  ●Floating tube diameter: 0.24 m    ●Length: 2.9 m    ●Quantity: 56
  ●Supposing the coverage area is D*L*Q = 0.24*2.9*56=38.976 m2

  ●A 20 m diameter tank with total measure area = 314.159 m2
  ●Float tube cover area percentage is 38.976/314.159 = 12.4 %
  ●Non-covered area is approx. 85 %


Skin&Pntoon IFR annual vapor loss is 174 t/yr
    (Annual vapor loss without any IFR=205 t/year; 205*0.85=174 t)


With Full Most IFR - Brick Style Honeycomb Type with Full Contact
There are two working conditions: normap operation and roof standing


Four categories of loss under normal operation:

    ◆rim seal loss         ◆withdrawal loss
    ◆deck fitting loss    ◆deck seam loss

Two categories of loss under roof standing:
    ◆standing idle loss ◆filling loss

Full Most's IFR annual vapor loss is only 2.2 t/yr







Case 1: Stored Liquid Test Under No Operations

Environmental Conditions

●Location: NE China (Panjin)   
●Diameter: 20 m
●Capacity: 5000 m³
●Stored liquid: naphtha
●Test period: every 8 days
●Temp. difference (est.) avg. high 15℃,avg. low 3℃
●Avg. daily solar radiation energy: 1135btu/ft² day.

■Full Most IFR - Brick Style Honeycomb Type with Full Contact can reduce 116 t/year

(138t-22t) more than Skin & Pontoon type does. Our IFR not only decreases VOC

emissions and reduces environmental pollution, but it also lowers the explosion hazards.








Case 2: VOC Concentration Test

Environmental Conditions
●Location: Taiwan, Yilan (Taiwan Petrochemical Plant)

●Date: 2015/03/19    
●Diameter: 17.38 m     ●Capacity: 3000 m³
●Liquid stored: M-xylene
●Design stored height: 12.127m

  Tank height at time of measurement: 9.5m
●The test is conducted after the liquid was stored for 9 days
●Testing instrument: Thermo Environmental Instruments TVA-1000



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What is an Internal Floating Roof?


Simply put, it is the roof that floats in the tank on top on the liquid's surface. It directly covers the liquid surface and blocks the direct contact between the liquid and the air, which can effectively reduce the emissions and stop the evaporation. Therefore, the more complete the liquid contact area between the Internal Floating Roof and the liquid storage surface, the better the effect.





Reasons for using Internal Floating Roofs (IFR) -

Brick Style Honeycomb Type with Full Contact

(1) Features:

  • Brick Style Honeycomb Type floating panel with high-strength structure:
    1.2t/ft2 plane compression. One floating panel buoyancy is over 4 times its dead weight load.
  • The stored liquid will not infiltrate to the honeycomb core because the 4 corners of the floating panels are fully welded. Gas leaking test is used in all 4 corners to ensure 100% sealing.
  • The frame design forms a stable structure. All floating panels are bolt-free, puncture-freem and every single unit can be replaced individually.
  • Two-way automatic vent design to balance the pressure during filling and withdrawal operations, and to prevent the floating roof from severely shaking.
  • All the parts can be put into the tank through the manhole.
  • Easy to install in a short time.
  • The structure is very strong, supporting more than 12 persons walking anywhere on the roof, exceeding API 650H requirements.
  • The Full Contact design can reach over 90% of VOC emissions reduction.
  • The related tests are measured and certified by third party: SGS
  • Meets NFPA 11 requirements
  • Meets API 650H requirements