In a study by NTT, 80% of network owners said contaminants were the root cause of network failures. Contamination occurs during the normal wear and tear of mating and de-mating. Particles and residue collect in the end cap, causing permanent damage. Once the interface is contaminated, the connection is at risk of being lost. Dirty connectors will cross-contaminant when they’re mated.
The most common containments are:
- Airborne particulates
- Residue from end caps (outgassing)
- Skin oil
- Alcohol residue
Dust, dirt, and airborne particulates will block the optical path that transmits data, resulting in signal degradation and eventual failure. The only real option to protect the network from downtime is to establish a regular inspection and cleaning protocol for the connectors.
How to Protect Performance
Fiber optic cables are strands of glass about the width of a human hair bundled together. They transmit light signals that are encoded with data that travel long distances at very high speeds. Whether the network runs on single or multimode cables, that light needs a clear pathway for the transmission. Consider that a single particle of dust on the fiber core can cause reflections in the light stream, downgrading performance and throwing high error rates. The inevitable result of degraded network performance is service disruption and network failure.
“There almost nothing more costly for datacenters and their customers than network failure.”
Eveyone loses revenue, compliance is compromised and network’s reputation is tarnished. When customer loyalty is damaged, it’s hard to recover.
Step 1: Inspection
It’s not enough to tell technicians to inspect the end caps. They need a protocol to follow, not a discretionary look and swipe. Most contaminants are too small for the naked eye so a tech needs the proper tools to start, but also a procedure to follow. Too often the cleaning process can actually end up contaminating the fibers.
Multi-fiber push-on connectors are a particular concern. The larger arrays make it easier to spread contaminants from fiber to fiber. But these fibers are the interface needed for 40 and 100G applications. But every endpoint – new or in-service should be inspected before mating. All devices including test equipment ports, adapters, and test cords should be inspected. Because mating can be a source of contamination, when a fiber is unplugged, it needs to be reinspected – even if it’s brand new or protected by a dust cap.
Technicians should be provided with either an optical or video microscope. The video microscope is best for navigating high-density areas. The screen is large for easy visualizations. The optical microscope is more affordable but less able to fit in tight spaces.
The technicians need to understand how to use the tools to identify contaminated endpoints. It’s suggested there be written procedures for them to follow during inspection and cleaning. Contaminants are the number one cause of fiber failure. The response must be consistent, not at the discretion of different employees or contractors.
2. What to Clean
While every endpoint point should be inspected, not all will require cleaning. The IEC 61300-3-35 Basic Test and Measurement Procedures Standard for Fiber Optic Interconnecting Devices and Passive Components is standard but currently under revision in 2021. The goal is to provide pass-fail grading criteria based on the scratches and defects found in the fiber endpoint. The criteria for the fiber core are the most rigorous.
The IEC’s standardization is helpful. Understanding the criteria for cleanliness provides network engineers a proactive way forward, to minimize degradation and service disruption. Do not clean endpoints which pass the IEC standard. Cleaning creates the potential for static electricity which can easily pull in dust.
3. How to Clean
There are multiple ways for cleaning fiber to standard. There are dry cleaning and wet cleaning methods. The important thing is to take care during the cleaning process. Be very careful removing dust caps and protect the cable from skin oils by using a clean glove.
Attempt the dry-cleaning method first, using a cleaning pen. Follow the directions carefully and shield the fiber as much as possible from any airborne particles. After the cleaning, inspect the fiber again to make sure it meets standards. Then clean the port or panel connection points. Make sure everything is up meets certifications before you mate the cable. Cabling 1,2,3 offers dry cleaning products, that include LC, MTP, SC interface types.
If the dry method doesn’t work, a lint-free, absorbent fabric wipe treated lightly with solvent is the next step. Solvents help remove stubborn containments without generating static electricity. Add a small amount of solvent to the wipe. Be careful – if too much solvent is on the cloth, it can leave behind a residue of contaminants.
Specialized solvents have been developed to replace isopropyl alcohol (IPA). Designed especially for cleaning cable, they have a lower surface tension for removing debris and dissolving contaminants. These newer solvents also have anti-static properties that reduce dust attraction.
Wipe the surface once or twice with light pressure. It should conform to the surface being cleaned, confirming its touched the entire element. Follow the standard inspection protocol to check for cleanliness. If there appears to be solvent on the surface, get a clean dry cloth and remove it carefully. Without solvent, the dry wipe can cause static electricity.
Cleaning Isn’t Sexy – Just Essentia
You can ignore regular inspection and cleaning procedures, but that doesn’t stop contamination. It shouldn’t take a service disruption to recognize that preventative maintenance is key to network performance. Get started today, with these simple steps.
- Write an inspection/cleaning procedure that explains what to do and the order to do it. Make sure it includes tools and equipment. A simple slide show for training can be a quick reference on the job.
- Make sure techs have the tools they need to identify contaminated interfaces and know how to use them. Choose the tools that are best for your environment. Cost is important but they need to work within your infrastructure.
- If you need a separate SOP for the cleaning process, make one. A video or webinar might be helpful when techs are doing the cleaning.
- Make it a practice to inspect everything and reinspect after cleaning.
If you keep the connections clean, the network performance will be consistently strong, with fewer service disruptions and downtime.