Source: Sharecast
The deal - which is expected to close in the second half of next year - along with the recently-announced sale of Smiths Interconnect, represents "significant further progress on the strategic actions announced in January 2025", it said.
"This repositions Smiths as a focused, high-performance, industrial engineering company, and delivers significant value for all stakeholders."
Smiths plans to return a large portion of the net cash proceeds from the proposed transaction to shareholders and will provide an update on timing and mechanism in due course.
Chief executive Roland Carter said the company had reached "another significant milestone".
"This builds on our recently announced sale of Smiths Interconnect and demonstrates strong execution against the strategic actions we set out in January centred on value creation," he said. "We are focusing Smiths as a premium industrial engineering company specialising in flow management and thermal solutions, and today's announcement positions us strongly to deliver enhanced growth and returns."
At 0955 GMT, the shares were up 1.4% at 2,464p.
Dan Coatsworth, head of markets at AJ Bell, said: "Smiths has got a good price for the unit which should please shareholders, particularly as they are in line for a cash payout.
"Selling the Detection business will dramatically change the revenue split in the rest of the group. Detection accounted for 29% of revenue in the past financial year, the second biggest contributor to the group. Post-separation, the seals-to-filtration unit John Crane will become even more dominant within Smiths, as will the temperature management arm Flex-Tek.
"One might expect a tighter focus on specialist engineering to entice investors to pay a higher multiple of earnings for the shares. This event has already happened, with the shares having already jumped from 13 times forward earnings a year ago to 19.2-times. The market has clearly bought into the story that Smiths was in break-up mode, and investors have tried to stay one step ahead of the curve."