In hydraulic systems across steel mills, foundries, and offshore drilling rigs, the application of fire-resistant PJ thermal sleeves is a mandatory safety standard. However, acquiring the right materials is only half the battle. Selecting the incorrect size can cause engineers face many difficulties during hose insertion, or significantly compromise the sleeve's insulation efficiency.
This article VHE will provide a detailed instruction on how to accurately measure and select the technically appropriate size for fire-resistant PJ sleeves, drawing on our extensive years of experience in custom sleeving and assembly.
1. Why is choosing the correct size for fire-resistant sleeves crucial?
Sizing a fire-resistant sleeve is typically based on matching the inside diameter (ID) of the sleeve to the outside diameter (OD) of the hydraulic hose.
- If the size is too tight: The friction between the hose's rubber jacket and the internal fibreglass layer of the fire-resistant PJ sleeve becomes immense. This makes the sleeving process (especially for long hoses) virtually impossible, causing the fibreglass to fray or the silicone coating to tear and deform.
- If the size is too loose: It results in unnecessary material waste and inflated costs. Furthermore, an excessive gap allows fluids and dirt to easily penetrate the interior, significantly compromising the effectiveness of the thermal insulation sleeve.
2. Guide to Measuring and Sizing Heat-Resistant PJ Fire Sleeves
To select the exact size for the red silicone-coated fibreglass thermal sleeve, you need to take actual measurements using a calliper by following these 3 steps:
- Step 1: Measure the hydraulic hose's Outside Diameter (OD). Use a calliper to measure the outermost diameter of the hose section you intend to sleeve. Take measurements at several different points to determine the maximum OD value. (Note: Absolutely never use the inside diameter of the hydraulic hose to determine the PJ sleeve size.
- Step 2: Measure the Fitting's Outside Diameter (Fitting OD) If the hydraulic hose is already pre-crimped and the fittings cannot be removed, it is mandatory to measure the largest outside diameter of the fitting assembly (e.g., the crimp ferrule or the hex nut). The fire-resistant PJ sleeve's inner diameter must exceed this measurement so it can be successfully slipped over the ends.
- Step 3: Add standard clearance. Once you have identified the largest dimension from Steps 1 and 2, DO NOT choose a PJ sleeve size that matches that measurement exactly. Instead, you must add a tolerance margin to ensure smooth insertion. The general formula recommended by VHE engineers is:
- PJ Sleeve Inside Diameter (ID) = Maximum measured dimension + 1.5mm to 3.0mm (depending on the length of the hose being sleeved).
3. Common Fire-Resistant PJ Sleeve Sizing Chart
Below is a recommended sizing guide for PJ thermal insulation fire sleeves based on the hydraulic hose's outside diameter (applicable to un-crimped hoses).
| Hose Outside Diameter (Hose OD) | Recommended PJ Sleeve Size (Sleeve ID) | Common Size Codes |
| 8mm - 10mm | ID 13mm | ID13 |
| 12mm - 14mm | ID 16mm | ID16 |
| 16mm - 19mm | ID 22mm | ID22 |
| 24mm - 28mm | ID 32mm | ID32 |
| 34mm - 36mm | ID 40mm | ID40 |
| 44mm - 47mm | ID 51mm | ID51 |
(Note: This table is for reference purposes only. If your system involves multiple cable bundles or complex fittings, please contact VHE engineers for technical consultation.
4. Quick Sleeving Tips for Installing PJ Fire-Resistant Sleeves
Even when the correct size is selected, inserting fire-resistant PJ sleeves over 5 meters long still requires significant effort due to friction. VHE shares some practical workshop tips:
- Use compressed air: Blowing compressed air into the gap between the sleeve and the rubber hose creates an air cushion, making the pushing process much smoother.
- Secure both ends: After insertion, it is mandatory to use stainless steel hose clamps or specialized heat-resistant silicone tape to tightly seal both cut ends. This prevents fibreglass fraying and stops oil and grease from seeping back inside.
5. VHE – A Reputable Nationwide Wholesale Distributor & Custom Assembly Partner for PJ Fire Sleeves
Vina Hydraulic Equipment Joint Stock Company (VHE) is a premier wholesale and retail distributor of protective materials for heavy industrial piping. We operate large-scale warehouse systems in Ho Chi Minh City and Hanoi, consistently maintaining thousands of meters of ready stock.
- Diverse size range: We supply a comprehensive range of sizes from ID5 to ID150, accommodating all hose and cable cross-sections.
- Comprehensive custom assembly services: The VHE engineering team undertakes custom cutting according to drawings, hose crimping, and the precise pre-installation of PJ fire-resistant sleeves before delivery to the factory. This helps customers maximize their savings on installation time.
If you are still unsure about material takeoffs or size selection, please contact VHE's sales department right away. Our experts are always ready to provide a completely free technical consultation!
- Consultation & Support (Zalo): 0903 067 588
- Support Email: [email protected]
- Office Address: 31, D20 Street, Phuoc Long Ward, Ho Chi Minh City, Vietnam.
