Multiplace Delivery System

Monthly Hyperbaric Safety Notice: October 2006

Titanium and the Hyperbaric Chamber

In this notice, deciding if a piece of equipment having titanium components will be allowed in the hyperbaric chamber will be presented.

Background

The 2005 NFPA 99 Health Care Facilities Handbook, 20.3.25* prohibits equipment made from cerium, magnesium and magnesium alloys in the hyperbaric chamber. There is concern expressed within the handbook regarding the potential risk of titanium products. The concern is that if a piece of titanium is broken, enough energy could be produced by the stress fracture to ignite the titanium in a high oxygen environment. The NFPA handbook states that this is not a concern in hyperbaric air.⁽¹⁾

Safety Issue

All equipment taken into a hyperbaric chamber should be evaluated for any associated risk. There are many good case histories and I have heard verbal witness regarding the explosive flammability of titanium. I wear glasses and the frames are made of a titanium alloy. When I first looked at this issue for my glasses we found that even if we could break them fast enough and hard enough to create a hazard…the titanium would probably oxidize on the broken ends before any kind of ignition would be produced. Currently we looked at whether the PMT Corp., HALO System Model 1233 containing titanium components was safe to use in the chamber. There are many alloys and forms of titanium. To protect the patients and staff we should not make assumptions.

Solid titanium is resistant to ignition in oxygen and air in temperatures up to 700 degrees F / 371.11 degrees C. It has been shown that ignition could not be started at high pressure even in 35% oxygen. However, once ignition starts, it will continue in environments with much lower levels of oxygen.⁽²⁾ The Material Safety Data Sheet from Electronic Space Products International for titanium (Ti); gives solid titanium a (low) 0 and powdered titanium a (high) 4 flammability scale. The auto ignition temperature for solid titanium is 2,192 degrees F / 1,200 degrees C, 896 degrees F / 480 degrees C for fine particles in a cloud form and 860 degrees F / 460 degrees C for a -100 mesh.⁽³⁾ Titanium in a powdered or fine form is very volatile as little as 0.002 – 0.003 oz/ft3 will ignite in 9% oxygen / balance helium or 3% oxygen / balance carbon dioxide.⁽⁴⁾

The PMT HALO System Model 1233 has two titanium components. The manufacture provided the tensile strength of those components. The hardware screws have a tensile strength of 55 Kpsi and the skull pins have a tensile strength of 145.8 Kpsi (Kpsi= kilo pounds per square inch, 1 Kpsi = 1000 pounds per square inch). The PMT Corp. sent us a letter including the statement that there was no risk of fire or explosion in our application. Their concern was only for the patient / skull interface and if there would be any changes due to the hyperbaric exposure.⁽⁵⁾

Equipment made of titanium should be evaluated before its use in the chambers. There are different types of titanium alloys and forms of titanium. Each product should be evaluated before use. I did not find any hazard caused by the titanium in the PMT HALO System. It is unlikely that a patient wearing a HALO will be able to produce the type of energy required to break the titanium components of the device, creating the kind of hazard expressed in the NFPA document. Further, multiplace chambers operate under the threshold temperatures for any kind of flammability concern with solid titanium. The loose powder or fines of titanium that are a concern are not present with this device. Any amount of powder, or filings, should never be allowed into the chamber.

Key Operational Issues

Evaluate each piece of equipment containing titanium or titanium alloys before using in the chamber.
Solid titanium is safe to use in the chamber during normal operations.

Bottom Line

Evaluate equipment before use. Solid titanium poses little or no risk during normal hyperbaric operations. Never allow any powdered or loose particles of titanium in the chamber. Documentation of the evaluation process is important.

Reading Assignment/References

NFPA 99 Health Care Facilities Handbook 2005 edition, 20.3.2.5
Corrosion Resistance of titanium, Titanium Materials Corporation, TIMET, pp20 figures 13 & 14
Electronics Space Products International, MSDS Sheet, Titanium, (Ti)
Safety-Related Problems in the Titanium Industry in the last 50 years, Poulsen, JOM, 52 (5) (2000), Safety Guidelines, pg 5 & 6, #5
Personal communications with PMT Corp.

Contributing Author: James Bell, CHT, EMT

James Bell Jim has over 25 years experience in the operation and maintenance of multiplace hyperbaric chambers. He serves as safety director and lead hyperbaric technologist at Hennepin County Medical Center, in Minneapolis, Minnesota, USA. Jim is a certified hyperbaric technologist, and an Undersea and Hyperbaric Medical Society facility accreditation surveyor.

Full Panel of Safety and Technical Correspondents

Previous Multiplace Safety Notices: